Apparatus for transmitting broadcast signals, apparatus for receiving broadcast signals, method for transmitting broadcast signals and method for receiving broadcast signals

ABSTRACT

The present invention provides a method of transmitting broadcast signals. The method includes, formatting, by an input formatting block, input streams into plural PLPs (Physical Layer Pipes); encoding, by an encoder, data in the plural PLPs; time interleaving, by a time interleaver, the encoded data in the plural PLPs, wherein the time interleaving includes: cell interleaving, by a cell interleaver, the encoded data by permuting cells in a FEC (Forward Error Correction) block in the plural PLPs; frame mapping, by a framer, the time interleaved data onto at least one signal frame; and waveform modulating, by a waveform block, the mapped data in the at least one signal frame and transmitting, by the waveform block, broadcast signals having the modulated data.

This application is a continuation of U.S. patent application Ser. No.14/712,021 filed May 14, 2015, which claims the benefit of U.S.Provisional Application No. 62/010,436, filed on Jun. 10, 2014, which ishereby incorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for transmitting broadcastsignals, an apparatus for receiving broadcast signals and methods fortransmitting and receiving broadcast signals.

2. Discussion of the Related Art

As analog broadcast signal transmission comes to an end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

That is, a digital broadcast system can provide HD (high definition)images, multi-channel audio and various additional services. However,data transmission efficiency for transmission of large amounts of data,robustness of transmission/reception networks and network flexibility inconsideration of mobile reception equipment need to be improved fordigital broadcast.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an apparatus fortransmitting broadcast signals and an apparatus for receiving broadcastsignals for future broadcast services and methods for transmitting andreceiving broadcast signals for future broadcast services.

An object of the present invention is to provide an apparatus and methodfor transmitting broadcast signals to multiplex data of a broadcasttransmission/reception system providing two or more different broadcastservices in a time domain and transmit the multiplexed data through thesame RF signal bandwidth and an apparatus and method for receivingbroadcast signals corresponding thereto.

Another object of the present invention is to provide an apparatus fortransmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals toclassify data corresponding to services by components, transmit datacorresponding to each component as a data pipe, receive and process thedata

Still another object of the present invention is to provide an apparatusfor transmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals tosignal signaling information necessary to provide broadcast signals.

To achieve the object and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, thepresent invention provides a method of transmitting broadcast signals.The method of transmitting broadcast signals includes formatting, by aninput formatting block, input streams into plural PLPs (Physical LayerPipes); encoding, by an encoder, data in the plural PLPs; timeinterleaving, by a time interleaver, the encoded data in the pluralPLPs, wherein the time interleaving includes: cell interleaving, by acell interleaver, the encoded data by permuting cells in a FEC (ForwardError Correction) block in the plural PLPs; frame mapping, by a framer,the time interleaved data onto at least one signal frame; and waveformmodulating, by a waveform block, the mapped data in the at least onesignal frame and transmitting, by the waveform block, broadcast signalshaving the modulated data.

Preferably, the cell interleaving further includes: writing the cells inthe FEC block into a memory linearly, and reading the cells from thememory randomly by using a permutation sequence.

Preferably, the permutation sequence is different for each FEC block inthe plural PLPs.

Preferably, the permutation sequences for each FEC block are determinedby shifting a basic permutation sequence differently.

Preferably, the permutation sequence is generated by adding a shiftingvalue to the basic permutation sequence, and by applying modulooperation with a number of cells in the FEC block,

wherein the shifting value is different for each FEC block in the pluralPLPs.

Preferably, the basic permutation sequence is a pseudo random sequence.

Preferably, the time interleaving further includes: block interleaving,by a block interleaver, at least one TI (Time Interleaving) blockincluding at least one of the FEC blocks, and convolutionalinterleaving, by a convolutional delay line block, the block interleavedat least one TI block.

Preferably, the encoding data in the plural PLPs further includes: FECencoding, by a FEC encoder, the data in the plural PLPs, bitinterleaving, by a bit interleaver, the FEC encoded data in the pluralPLPs, and constellation mapping, by a mapper, the bit interleaved datato the FEC block by mapping onto constellations.

In other aspect, the present invention provides a method of receivingbroadcast signals. The method of receiving broadcast signals includesreceiving, by a waveform block, broadcast signals having at least onesignal frame and demodulating, by the waveform block, data in the atleast one signal frame; frame parsing, by a frame parser, thedemodulated data in the at least one signal frame by demapping pluralPLPs (Physical Layer Pipes); time deinterleaving, by a timedeinterleaver, data in the plural PLPs, wherein the time deinterleavingincludes: cell deinterleaving, by a cell deinterleaver, the data in theplural PLPs by permuting cells in a FEC (Forward Error Correction) blockin the plural PLPs;

decoding, by a decoder, the time deinterleaved data in the plural PLPs;and output processing, by an output processing block, the decoded datain the plural PLPs to output output streams.

Preferably, the cell deinterleaving further includes: writing the cellsin the FEC block into a memory randomly by using a permutation sequence,and reading the cells from the memory linearly.

Preferably, the permutation sequence is different for each FEC block inthe plural PLPs.

Preferably, the permutation sequences for each FEC block are determinedby shifting a basic permutation sequence differently.

Preferably, the permutation sequence is generated by adding a shiftingvalue to the basic permutation sequence, and by applying modulooperation with a number of cells in the FEC block,

wherein the shifting value is different for each FEC block in the pluralPLPs.

Preferably, the basic permutation sequence is a pseudo random sequence.

Preferably, the time deinterleaving further includes: convolutionaldeinterleaving, by a convolutional delay line block, data in the pluralPLPs, and block deinterleaving, by a block deinterleaver, theconvolutional deinterleaved data including at least one of the FECblocks.

Preferably, the decoding the time deinterleaved data in the plural PLPsfurther includes: constellation demapping, by a demapper, the timedeinterleaved data from constellations, bit deinterleaving, by a bitdeinterleaver, the demapped data in the plural PLPs, and FEC decoding,by a FEC decoder, the bit deinterleaved data in the plural PLPs.

In another aspect, the present invention provides an apparatus fortransmitting broadcast signals. The apparatus for transmitting broadcastsignals includes an input formatting block that formats input streamsinto plural PLPs (Physical Layer Pipes); an encoder that encodes data inthe plural PLPs; a time interleaver that time interleaves the encodeddata in the plural PLPs, wherein the time interleaver includes: a cellinterleaver that cell interleaves the encoded data by permuting cells ina FEC (Forward Error Correction) block in the plural PLPs; a framer thatmaps the time interleaved data onto at least one signal frame; and awaveform block that waveform modulates the mapped data in the at leastone signal frame and that transmits broadcast signals having themodulated data.

Preferably, the cell interleaver writes the cells in the FEC block intoa memory linearly, and wherein the cell interleaver reads the cells fromthe memory randomly by using a permutation sequence.

Preferably, the permutation sequence is different for each FEC block inthe plural PLPs.

Preferably, the permutation sequences for each FEC block are determinedby shifting a basic permutation sequence differently.

Preferably, the permutation sequence is generated by adding a shiftingvalue to the basic permutation sequence, and by applying modulooperation with a number of cells in the FEC block,

wherein the shifting value is different for each FEC block in the pluralPLPs.

Preferably, the basic permutation sequence is a pseudo random sequence.

Preferably, the time interleaver further includes: a block interleaverthat block interleaves at least one TI (Time Interleaving) blockincluding at least one of the FEC blocks, and a convolutional delay lineblock that convolutional interleaves the block interleaved at least oneTI block.

Preferably, the encoder further includes: a FEC encoder that FEC encodesthe data in the plural PLPs,

a bit interleaver that bit interleaves the FEC encoded data in theplural PLPs, and a constellation mapper that maps the bit interleaveddata to the FEC block by mapping onto constellations.

In another aspect, the present invention provides an apparatus forreceiving broadcast signals. The apparatus for receiving broadcastsignals includes a waveform block that receives broadcast signals havingat least one signal frame and demodulates data in the at least onesignal frame;

a frame parser that parses the demodulated data in the at least onesignal frame by demapping plural PLPs (Physical Layer Pipes); a timedeinterleaver that time deinterleaves data in the plural PLPs, whereinthe time deinterleaver includes: a cell deinterleaver that celldeinterleaves the data in the plural PLPs by permuting cells in a FEC(Forward Error Correction) block in the plural PLPs; a decoder thatdecodes the time deinterleaved data in the plural PLPs; and an outputprocessing block that output processes the decoded data in the pluralPLPs to output output streams.

Preferably, the cell deinterleaver writes the cells in the FEC blockinto a memory randomly by using a permutation sequence, and wherein thecell deinterleaver reads the cells from the memory linearly.

Preferably, the permutation sequence is different for each FEC block inthe plural PLPs.

Preferably, the permutation sequences for each FEC block are determinedby shifting a basic permutation sequence differently.

Preferably, the permutation sequence is generated by adding a shiftingvalue to the basic permutation sequence, and by applying modulooperation with a number of cells in the FEC block,

wherein the shifting value is different for each FEC block in the pluralPLPs.

Preferably, the basic permutation sequence is a pseudo random sequence.

Preferably, the time deinterleaver further includes: a convolutionaldelay line block that convolutional deinterleaves data in the pluralPLPs, and a block deinterleaver that block deinterleaves theconvolutional deinterleaved data including at least one of the FECblocks.

Preferably, the decoder further includes: a constellation demapper thatdemaps the time deinterleaved data from constellations, a bitdeinterleaver that bit deinterleaves the demapped data in the pluralPLPs, and a FEC decoder that FEC decodes the bit deinterleaved data inthe plural PLPs.

The present invention can process data according to servicecharacteristics to control QoS (Quality of Services) for each service orservice component, thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same RF signalbandwidth.

The present invention can improve data transmission efficiency andincrease robustness of transmission/reception of broadcast signals usinga MIMO system.

According to the present invention, it is possible to provide broadcastsignal transmission and reception methods and apparatus capable ofreceiving digital broadcast signals without error even with mobilereception equipment or in an indoor environment.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

FIG. 8 illustrates an OFDM generation block according to an embodimentof the present invention.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

FIG. 26 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

FIG. 28 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

FIG. 29 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 30 is a view illustrating a coding & modulation module according toanother embodiment of the present invention.

FIG. 31 is a view illustrating a periodic-random I/Q interleavingtechnology according to an embodiment of the present invention.

FIG. 32 is a view illustrating a Q1-delay process in the case of 2D-SSD,according to an embodiment of the present invention.

FIG. 33 is a view illustrating operation of the periodic-random I/Qinterleaver in the case of 2D-SSD, according to an embodiment of thepresent invention.

FIG. 34 is a view illustrating operation of the periodic-random I/Qinterleaving technology in the case of 2D-SSD when N is 24, according toan embodiment of the present invention.

FIG. 35 is a view illustrating a Q2-delay process in the case of 4D-SSD,according to an embodiment of the present invention.

FIG. 36 is a view illustrating operation of the periodic-random I/Qinterleaver in the case of 4D-SSD, according to an embodiment of thepresent invention.

FIG. 37 is a view illustrating operation of the periodic-random I/Qinterleaving technology in the case of 4D-SSD when N is 24, according toan embodiment of the present invention.

FIG. 38 is a detailed block diagram of a demapping & decoding moduleaccording to another embodiment of the present invention.

FIG. 39 is a view illustrating a periodic-random I/Q deinterleavingtechnology according to an embodiment of the present invention.

FIG. 40 illustrates a part of a broadcast signal transmitter fornext-generation broadcast service according to another embodiment of thepresent invention.

FIG. 41 is a view illustrating a basic switch structure according to anembodiment of the present invention.

FIG. 42 is a view mathematically expressing linear writing & randomreading operation of the cell interleaver according to anotherembodiment of the present invention.

FIG. 43 is a view mathematically expressing a permutation sequencegenerating method of the cell interleaver according to anotherembodiment of the present invention cell interleaver.

FIG. 44 illustrates a part of a broadcast signal receiver fornext-generation broadcast service including a cell deinterleaveraccording to another embodiment of the present invention.

FIG. 45 is a view illustrating a broadcast signal transmitting methodaccording to an embodiment of the present invention.

FIG. 46 is a view illustrating a broadcast signal transmitter accordingto an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although most terms used in the present invention have been selectedfrom general ones widely used in the art, some terms have beenarbitrarily selected by the applicant and their meanings are explainedin detail in the following description as needed. Thus, the presentinvention should be understood based upon the intended meanings of theterms rather than their simple names or meanings.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, aUHDTV service, etc. The present invention may process broadcast signalsfor the future broadcast services through non-MIMO (Multiple InputMultiple Output) or MIMO according to one embodiment. A non-MIMO schemeaccording to an embodiment of the present invention may include a MISO(Multiple Input Single Output) scheme, a SISO (Single Input SingleOutput) scheme, etc.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas.

The present invention may defines three physical layer (PL) profiles(base, handheld and advanced profiles), each optimized to minimizereceiver complexity while attaining the performance required for aparticular use case. The physical layer (PHY) profiles are subsets ofall configurations that a corresponding receiver should implement.

The three PHY profiles share most of the functional blocks but differslightly in specific blocks and/or parameters. Additional PHY profilescan be defined in the future. For the system evolution, future profilescan also be multiplexed with the existing profiles in a single RFchannel through a future extension frame (FEF). The details of each PHYprofile are described below.

1. Base Profile

The base profile represents a main use case for fixed receiving devicesthat are usually connected to a roof-top antenna. The base profile alsoincludes portable devices that could be transported to a place butbelong to a relatively stationary reception category. Use of the baseprofile could be extended to handheld devices or even vehicular by someimproved implementations, but those use cases are not expected for thebase profile receiver operation.

Target SNR range of reception is from approximately 10 to 20 dB, whichincludes the 15 dB SNR reception capability of the existing broadcastsystem (e.g. ATSC A/53). The receiver complexity and power consumptionis not as critical as in the battery-operated handheld devices, whichwill use the handheld profile. Key system parameters for the baseprofile are listed in below table 1.

TABLE 1 LDPC codeword length 16K, 64K bits Constellation size 4~10 bpcu(bits per channel use) Time de-interleaving memory size ≦2¹⁹ data cellsPilot patterns Pilot pattern for fixed reception FFT size 16K, 32Kpoints

2. Handheld Profile

The handheld profile is designed for use in handheld and vehiculardevices that operate with battery power. The devices can be moving withpedestrian or vehicle speed. The power consumption as well as thereceiver complexity is very important for the implementation of thedevices of the handheld profile. The target SNR range of the handheldprofile is approximately 0 to 10 dB, but can be configured to reachbelow 0 dB when intended for deeper indoor reception.

In addition to low SNR capability, resilience to the Doppler Effectcaused by receiver mobility is the most important performance attributeof the handheld profile. Key system parameters for the handheld profileare listed in the below table 2.

TABLE 2 LDPC codeword length 16K bits Constellation size 2~8 bpcu Timede-interleaving memory size ≦2¹⁸ data cells Pilot patterns Pilotpatterns for mobile and indoor reception FFT size 8K, 16K points

3. Advanced profile

The Advanced Profile Provides Highest Channel Capacity at the Cost ofMore implementation complexity. This profile requires using MIMOtransmission and reception, and UHDTV service is a target use case forwhich this profile is specifically designed. The increased capacity canalso be used to allow an increased number of services in a givenbandwidth, e.g., multiple SDTV or HDTV services.

The target SNR range of the advanced profile is approximately 20 to 30dB. MIMO transmission may initially use existing elliptically-polarizedtransmission equipment, with extension to full-power cross-polarizedtransmission in the future. Key system parameters for the advancedprofile are listed in below table 3.

TABLE 3 LDPC codeword length 16K, 64K bits Constellation size 8~12 bpcuTime de-interleaving memory size ≦2¹⁹ data cells Pilot patterns Pilotpattern for fixed reception FFT size 16K, 32K points

In this case, the base profile can be used as a profile for both theterrestrial broadcast service and the mobile broadcast service. That is,the base profile can be used to define a concept of a profile whichincludes the mobile profile. Also, the advanced profile can be dividedadvanced profile for a base profile with MIMO and advanced profile for ahandheld profile with MIMO. Moreover, the three profiles can be changedaccording to intention of the designer.

The following terms and definitions may apply to the present invention.The following terms and definitions can be changed according to design.

auxiliary stream: sequence of cells carrying data of as yet undefinedmodulation and coding, which may be used for future extensions or asrequired by broadcasters or network operators

base data pipe: data pipe that carries service signaling data

baseband frame (or BBFRAME): set of K_(bch) bits which form the input toone FEC encoding process (BCH and LDPC encoding)

cell: modulation value that is carried by one carrier of the OFDMtransmission

coded block: LDPC-encoded block of PLS1 data or one of the LDPC-encodedblocks of PLS2 data

data pipe: logical channel in the physical layer that carries servicedata or related metadata, which may carry one or multiple service(s) orservice component(s).

data pipe unit: a basic unit for allocating data cells to a DP in aframe.

data symbol: OFDM symbol in a frame which is not a preamble symbol (theframe signaling symbol and frame edge symbol is included in the datasymbol)

DP_ID: this 8-bit field identifies uniquely a DP within the systemidentified by the SYSTEM_ID

dummy cell: cell carrying a pseudo-random value used to fill theremaining capacity not used for PLS signaling, DPs or auxiliary streams

emergency alert channel: part of a frame that carries EAS informationdata

frame: physical layer time slot that starts with a preamble and endswith a frame edge symbol

frame repetition unit: a set of frames belonging to same or differentphysical layer profile including a FEF, which is repeated eight times ina super-frame

fast information channel: a logical channel in a frame that carries themapping information between a service and the corresponding base DP

FECBLOCK: set of LDPC-encoded bits of a DP data

FFT size: nominal FFT size used for a particular mode, equal to theactive symbol period T_(S) expressed in cycles of the elementary periodT

frame signaling symbol: OFDM symbol with higher pilot density used atthe start of a frame in certain combinations of FFT size, guard intervaland scattered pilot pattern, which carries a part of the PLS data

frame edge symbol: OFDM symbol with higher pilot density used at the endof a frame in certain combinations of FFT size, guard interval andscattered pilot pattern

frame-group: the set of all the frames having the same PHY profile typein a super-frame.

future extension frame: physical layer time slot within the super-framethat could be used for future extension, which starts with a preamble

Futurecast UTB system: proposed physical layer broadcasting system, ofwhich the input is one or more MPEG2-TS or IP or general stream(s) andof which the output is an RF signal

input stream: A stream of data for an ensemble of services delivered tothe end users by the system.

normal data symbol: data symbol excluding the frame signaling symbol andthe frame edge symbol

PHY profile: subset of all configurations that a corresponding receivershould implement

PLS: physical layer signaling data consisting of PLS1 and PLS2

PLS1: a first set of PLS data carried in the FSS symbols having a fixedsize, coding and modulation, which carries basic information about thesystem as well as the parameters needed to decode the PLS2

NOTE: PLS1 data remains constant for the duration of a frame-group.

PLS2: a second set of PLS data transmitted in the FSS symbol, whichcarries more detailed PLS data about the system and the DPs

PLS2 dynamic data: PLS2 data that may dynamically change frame-by-frame

PLS2 static data: PLS2 data that remains static for the duration of aframe-group

preamble signaling data: signaling data carried by the preamble symboland used to identify the basic mode of the system

preamble symbol: fixed-length pilot symbol that carries basic PLS dataand is located in the beginning of a frame

NOTE: The preamble symbol is mainly used for fast initial band scan todetect the system signal, its timing, frequency offset, and FFT-size.

reserved for future use: not defined by the present document but may bedefined in future

super-frame: set of eight frame repetition units

time interleaving block (TI block): set of cells within which timeinterleaving is carried out, corresponding to one use of the timeinterleaver memory

TI group: unit over which dynamic capacity allocation for a particularDP is carried out, made up of an integer, dynamically varying number ofXFECBLOCKs.

NOTE: The TI group may be mapped directly to one frame or may be mappedto multiple frames. It may contain one or more TI blocks.

Type 1 DP: DP of a frame where all DPs are mapped into the frame in TDMfashion

Type 2 DP: DP of a frame where all DPs are mapped into the frame in FDMfashion

XFECBLOCK: set of N cells carrying all the bits of one LDPC FECBLOCKcells

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

The apparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can includean input formatting block 1000, a BICM (Bit interleaved coding &modulation) block 1010, a frame structure block 1020, an OFDM(Orthogonal Frequency Division Multiplexing) generation block 1030 and asignaling generation block 1040. A description will be given of theoperation of each module of the apparatus for transmitting broadcastsignals.

IP stream/packets and MPEG2-TS are the main input formats, other streamtypes are handled as General Streams. In addition to these data inputs,Management Information is input to control the scheduling and allocationof the corresponding bandwidth for each input stream. One or multiple TSstream(s), IP stream(s) and/or General Stream(s) inputs aresimultaneously allowed.

The input formatting block 1000 can demultiplex each input stream intoone or multiple data pipe(s), to each of which an independent coding andmodulation is applied. The data pipe (DP) is the basic unit forrobustness control, thereby affecting quality-of-service (QoS). One ormultiple service(s) or service component(s) can be carried by a singleDP. Details of operations of the input formatting block 1000 will bedescribed later.

The data pipe is a logical channel in the physical layer that carriesservice data or related metadata, which may carry one or multipleservice(s) or service component(s).

Also, the data pipe unit: a basic unit for allocating data cells to a DPin a frame.

In the BICM block 1010, parity data is added for error correction andthe encoded bit streams are mapped to complex-value constellationsymbols. The symbols are interleaved across a specific interleavingdepth that is used for the corresponding DP. For the advanced profile,MIMO encoding is performed in the BICM block 1010 and the additionaldata path is added at the output for MIMO transmission. Details ofoperations of the BICM block 1010 will be described later.

The Frame Building block 1020 can map the data cells of the input DPsinto the OFDM symbols within a frame. After mapping, the frequencyinterleaving is used for frequency-domain diversity, especially tocombat frequency-selective fading channels. Details of operations of theFrame Building block 1020 will be described later.

After inserting a preamble at the beginning of each frame, the OFDMGeneration block 1030 can apply conventional OFDM modulation having acyclic prefix as guard interval. For antenna space diversity, adistributed MISO scheme is applied across the transmitters. In addition,a Peak-to-Average Power Reduction (PAPR) scheme is performed in the timedomain. For flexible network planning, this proposal provides a set ofvarious FFT sizes, guard interval lengths and corresponding pilotpatterns. Details of operations of the OFDM Generation block 1030 willbe described later.

The Signaling Generation block 1040 can create physical layer signalinginformation used for the operation of each functional block. Thissignaling information is also transmitted so that the services ofinterest are properly recovered at the receiver side. Details ofoperations of the Signaling Generation block 1040 will be describedlater.

FIGS. 2, 3 and 4 illustrate the input formatting block 1000 according toembodiments of the present invention. A description will be given ofeach figure.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention. FIG. 2 shows an input formatting module whenthe input signal is a single input stream.

The input formatting block illustrated in FIG. 2 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

The input to the physical layer may be composed of one or multiple datastreams. Each data stream is carried by one DP. The mode adaptationmodules slice the incoming data stream into data fields of the basebandframe (BBF). The system supports three types of input data streams:MPEG2-TS, Internet protocol (IP) and Generic stream (GS). MPEG2-TS ischaracterized by fixed length (188 byte) packets with the first bytebeing a sync-byte (0x47). An IP stream is composed of variable length IPdatagram packets, as signaled within IP packet headers. The systemsupports both IPv4 and IPv6 for the IP stream. GS may be composed ofvariable length packets or constant length packets, signaled withinencapsulation packet headers.

(a) shows a mode adaptation block 2000 and a stream adaptation 2010 forsignal DP and (b) shows a PLS generation block 2020 and a PLS scrambler2030 for generating and processing PLS data. A description will be givenof the operation of each block.

The Input Stream Splitter splits the input TS, IP, GS streams intomultiple service or service component (audio, video, etc.) streams. Themode adaptation module 2010 is comprised of a CRC Encoder, BB (baseband)Frame Slicer, and BB Frame Header Insertion block.

The CRC Encoder provides three kinds of CRC encoding for error detectionat the user packet (UP) level, i.e., CRC-8, CRC-16, and CRC-32. Thecomputed CRC bytes are appended after the UP. CRC-8 is used for TSstream and CRC-32 for IP stream. If the GS stream doesn't provide theCRC encoding, the proposed CRC encoding should be applied.

BB Frame Slicer maps the input into an internal logical-bit format. Thefirst received bit is defined to be the MSB. The BB Frame Slicerallocates a number of input bits equal to the available data fieldcapacity. To allocate a number of input bits equal to the BBF payload,the UP packet stream is sliced to fit the data field of BBF.

BB Frame Header Insertion block can insert fixed length BBF header of 2bytes is inserted in front of the BB Frame. The BBF header is composedof STUFFI (1 bit), SYNCD (13 bits), and RFU (2 bits). In addition to thefixed 2-Byte BBF header, BBF can have an extension field (1 or 3 bytes)at the end of the 2-byte BBF header.

The stream adaptation 2010 is comprised of stuffing insertion block andBB scrambler.

The stuffing insertion block can insert stuffing field into a payload ofa BB frame. If the input data to the stream adaptation is sufficient tofill a BB-Frame, STUFFI is set to ‘0’ and the BBF has no stuffing field.Otherwise STUFFI is set to ‘1’ and the stuffing field is insertedimmediately after the BBF header. The stuffing field comprises two bytesof the stuffing field header and a variable size of stuffing data.

The BB scrambler scrambles complete BBF for energy dispersal. Thescrambling sequence is synchronous with the BBF. The scrambling sequenceis generated by the feed-back shift register.

The PLS generation block 2020 can generate physical layer signaling(PLS) data. The PLS provides the receiver with a means to accessphysical layer DPs. The PLS data consists of PLS1 data and PLS2 data.

The PLS1 data is a first set of PLS data carried in the FSS symbols inthe frame having a fixed size, coding and modulation, which carriesbasic information about the system as well as the parameters needed todecode the PLS2 data. The PLS1 data provides basic transmissionparameters including parameters required to enable the reception anddecoding of the PLS2 data. Also, the PLS1 data remains constant for theduration of a frame-group.

The PLS2 data is a second set of PLS data transmitted in the FSS symbol,which carries more detailed PLS data about the system and the DPs. ThePLS2 contains parameters that provide sufficient information for thereceiver to decode the desired DP. The PLS2 signaling further consistsof two types of parameters, PLS2 Static data (PLS2-STAT data) and PLS2dynamic data (PLS2-DYN data). The PLS2 Static data is PLS2 data thatremains static for the duration of a frame-group and the PLS2 dynamicdata is PLS2 data that may dynamically change frame-by-frame.

Details of the PLS data will be described later.

The PLS scrambler 2030 can scramble the generated PLS data for energydispersal.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 3 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 3 shows a mode adaptation block of the input formatting block whenthe input signal corresponds to multiple input streams.

The mode adaptation block of the input formatting block for processingthe multiple input streams can independently process the multiple inputstreams.

Referring to FIG. 3, the mode adaptation block for respectivelyprocessing the multiple input streams can include an input streamsplitter 3000, an input stream synchronizer 3010, a compensating delayblock 3020, a null packet deletion block 3030, a head compression block3040, a CRC encoder 3050, a BB frame slicer 3060 and a BB headerinsertion block 3070. Description will be given of each block of themode adaptation block.

Operations of the CRC encoder 3050, BB frame slicer 3060 and BB headerinsertion block 3070 correspond to those of the CRC encoder, BB frameslicer and BB header insertion block described with reference to FIG. 2and thus description thereof is omitted.

The input stream splitter 3000 can split the input TS, IP, GS streamsinto multiple service or service component (audio, video, etc.) streams.

The input stream synchronizer 3010 may be referred as ISSY. The ISSY canprovide suitable means to guarantee Constant Bit Rate (CBR) and constantend-to-end transmission delay for any input data format. The ISSY isalways used for the case of multiple DPs carrying TS, and optionallyused for multiple DPs carrying GS streams.

The compensating delay block 3020 can delay the split TS packet streamfollowing the insertion of ISSY information to allow a TS packetrecombining mechanism without requiring additional memory in thereceiver.

The null packet deletion block 3030, is used only for the TS inputstream case. Some TS input streams or split TS streams may have a largenumber of null-packets present in order to accommodate VBR (variablebit-rate) services in a CBR TS stream. In this case, in order to avoidunnecessary transmission overhead, null-packets can be identified andnot transmitted. In the receiver, removed null-packets can bere-inserted in the exact place where they were originally by referenceto a deleted null-packet (DNP) counter that is inserted in thetransmission, thus guaranteeing constant bit-rate and avoiding the needfor time-stamp (PCR) updating.

The head compression block 3040 can provide packet header compression toincrease transmission efficiency for TS or IP input streams. Because thereceiver can have a priori information on certain parts of the header,this known information can be deleted in the transmitter.

For Transport Stream, the receiver has a-priori information about thesync-byte configuration (0x47) and the packet length (188 Byte). If theinput TS stream carries content that has only one PID, i.e., for onlyone service component (video, audio, etc.) or service sub-component (SVCbase layer, SVC enhancement layer, MVC base view or MVC dependentviews), TS packet header compression can be applied (optionally) to theTransport Stream. IP packet header compression is used optionally if theinput steam is an IP stream.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 4 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 4 illustrates a stream adaptation block of the input formattingmodule when the input signal corresponds to multiple input streams.

Referring to FIG. 4, the mode adaptation block for respectivelyprocessing the multiple input streams can include a scheduler 4000, an1-Frame delay block 4010, a stuffing insertion block 4020, an in-bandsignaling 4030, a BB Frame scrambler 4040, a PLS generation block 4050and a PLS scrambler 4060. Description will be given of each block of thestream adaptation block.

Operations of the stuffing insertion block 4020, the BB Frame scrambler4040, the PLS generation block 4050 and the PLS scrambler 4060correspond to those of the stuffing insertion block, BB scrambler, PLSgeneration block and the PLS scrambler described with reference to FIG.2 and thus description thereof is omitted.

The scheduler 4000 can determine the overall cell allocation across theentire frame from the amount of FECBLOCKs of each DP. Including theallocation for PLS, EAC and FIC, the scheduler generate the values ofPLS2-DYN data, which is transmitted as in-band signaling or PLS cell inFSS of the frame. Details of FECBLOCK, EAC and FIC will be describedlater.

The 1-Frame delay block 4010 can delay the input data by onetransmission frame such that scheduling information about the next framecan be transmitted through the current frame for in-band signalinginformation to be inserted into the DPs.

The in-band signaling 4030 can insert un-delayed part of the PLS2 datainto a DP of a frame.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

The BICM block illustrated in FIG. 5 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

As described above, the apparatus for transmitting broadcast signals forfuture broadcast services according to an embodiment of the presentinvention can provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS (quality of service) depends on characteristics of a serviceprovided by the apparatus for transmitting broadcast signals for futurebroadcast services according to an embodiment of the present invention,data corresponding to respective services needs to be processed throughdifferent schemes. Accordingly, the a BICM block according to anembodiment of the present invention can independently process DPs inputthereto by independently applying SISO, MISO and MIMO schemes to thedata pipes respectively corresponding to data paths. Consequently, theapparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can controlQoS for each service or service component transmitted through each DP.

(a) shows the BICM block shared by the base profile and the handheldprofile and (b) shows the BICM block of the advanced profile.

The BICM block shared by the base profile and the handheld profile andthe BICM block of the advanced profile can include plural processingblocks for processing each DP.

A description will be given of each processing block of the BICM blockfor the base profile and the handheld profile and the BICM block for theadvanced profile.

A processing block 5000 of the BICM block for the base profile and thehandheld profile can include a Data FEC encoder 5010, a bit interleaver5020, a constellation mapper 5030, an SSD (Signal Space Diversity)encoding block 5040 and a time interleaver 5050.

The Data FEC encoder 5010 can perform the FEC encoding on the input BBFto generate FECBLOCK procedure using outer coding (BCH), and innercoding (LDPC). The outer coding (BCH) is optional coding method. Detailsof operations of the Data FEC encoder 5010 will be described later.

The bit interleaver 5020 can interleave outputs of the Data FEC encoder5010 to achieve optimized performance with combination of the LDPC codesand modulation scheme while providing an efficiently implementablestructure. Details of operations of the bit interleaver 5020 will bedescribed later.

The constellation mapper 5030 can modulate each cell word from the bitinterleaver 5020 in the base and the handheld profiles, or cell wordfrom the Cell-word demultiplexer 5010-1 in the advanced profile usingeither QPSK, QAM-16, non-uniform QAM (NUQ-64, NUQ-256, NUQ-1024) ornon-uniform constellation (NUC-16, NUC-64, NUC-256, NUC-1024) to give apower-normalized constellation point, e₁. This constellation mapping isapplied only for DPs. Observe that QAM-16 and NUQs are square shaped,while NUCs have arbitrary shape. When each constellation is rotated byany multiple of 90 degrees, the rotated constellation exactly overlapswith its original one. This “rotation-sense” symmetric property makesthe capacities and the average powers of the real and imaginarycomponents equal to each other. Both NUQs and NUCs are definedspecifically for each code rate and the particular one used is signaledby the parameter DP_MOD filed in PLS2 data.

The SSD encoding block 5040 can precode cells in two (2D), three (3D),and four (4D) dimensions to increase the reception robustness underdifficult fading conditions.

The time interleaver 5050 can operates at the DP level. The parametersof time interleaving (TI) may be set differently for each DP. Details ofoperations of the time interleaver 5050 will be described later.

A processing block 5000-1 of the BICM block for the advanced profile caninclude the Data FEC encoder, bit interleaver, constellation mapper, andtime interleaver. However, the processing block 5000-1 is distinguishedfrom the processing block 5000 further includes a cell-worddemultiplexer 5010-1 and a MIMO encoding block 5020-1.

Also, the operations of the Data FEC encoder, bit interleaver,constellation mapper, and time interleaver in the processing block5000-1 correspond to those of the Data FEC encoder 5010, bit interleaver5020, constellation mapper 5030, and time interleaver 5050 described andthus description thereof is omitted.

The cell-word demultiplexer 5010-1 is used for the DP of the advancedprofile to divide the single cell-word stream into dual cell-wordstreams for MIMO processing. Details of operations of the cell-worddemultiplexer 5010-1 will be described later.

The MIMO encoding block 5020-1 can processing the output of thecell-word demultiplexer 5010-1 using MIMO encoding scheme. The MIMOencoding scheme was optimized for broadcasting signal transmission. TheMIMO technology is a promising way to get a capacity increase but itdepends on channel characteristics. Especially for broadcasting, thestrong LOS component of the channel or a difference in the receivedsignal power between two antennas caused by different signal propagationcharacteristics makes it difficult to get capacity gain from MIMO. Theproposed MIMO encoding scheme overcomes this problem using arotation-based pre-coding and phase randomization of one of the MIMOoutput signals.

MIMO encoding is intended for a 2×2 MIMO system requiring at least twoantennas at both the transmitter and the receiver. Two MIMO encodingmodes are defined in this proposal; full-rate spatial multiplexing(FR-SM) and full-rate full-diversity spatial multiplexing (FRFD-SM). TheFR-SM encoding provides capacity increase with relatively smallcomplexity increase at the receiver side while the FRFD-SM encodingprovides capacity increase and additional diversity gain with a greatcomplexity increase at the receiver side. The proposed MIMO encodingscheme has no restriction on the antenna polarity configuration.

MIMO processing is required for the advanced profile frame, which meansall DPs in the advanced profile frame are processed by the MIMO encoder.MIMO processing is applied at DP level. Pairs of the ConstellationMapper outputs NUQ (e_(1,i) and e_(2,i)) are fed to the input of theMIMO Encoder. Paired MIMO Encoder output (g1,i and g2,i) is transmittedby the same carrier k and OFDM symbol 1 of their respective TX antennas.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

The BICM block illustrated in FIG. 6 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

FIG. 6 illustrates a BICM block for protection of physical layersignaling (PLS), emergency alert channel (EAC) and fast informationchannel (FIC). EAC is a part of a frame that carries EAS informationdata and FIC is a logical channel in a frame that carries the mappinginformation between a service and the corresponding base DP. Details ofthe EAC and FIC will be described later.

Referring to FIG. 6, the BICM block for protection of PLS, EAC and FICcan include a PLS FEC encoder 6000, a bit interleaver 6010, and aconstellation mapper 6020.

Also, the PLS FEC encoder 6000 can include a scrambler, BCHencoding/zero insertion block, LDPC encoding block and LDPC paritypunturing block. Description will be given of each block of the BICMblock.

The PLS FEC encoder 6000 can encode the scrambled PLS 1/2 data, EAC andFIC section.

The scrambler can scramble PLS1 data and PLS2 data before BCH encodingand shortened and punctured LDPC encoding.

The BCH encoding/zero insertion block can perform outer encoding on thescrambled PLS 1/2 data using the shortened BCH code for PLS protectionand insert zero bits after the BCH encoding. For PLS 1 data only, theoutput bits of the zero insertion may be permutted before LDPC encoding.

The LDPC encoding block can encode the output of the BCH encoding/zeroinsertion block using LDPC code. To generate a complete coded block,C_(ldpc), parity bits, P_(ldpc) are encoded systematically from eachzero-inserted PLS information block, I_(ldpc), and appended after it.

C _(ldpc) =[I _(ldpc) P _(ldpc) ]=[i ₀ ,i ₁ , . . . i _(K) _(ldpc) ₋₁ ,p₀ ,p ₁ , . . . ,p _(N) _(ldpc) _(-K) _(ldpc) ₋₁]  [Expression 1]

The LDPC code parameters for PLS1 and PLS2 are as following table 4.

TABLE 4 Signaling K_(ldpc) code Type K_(sig) K_(bch) N_(bch) _(—)_(parity) (=N_(bch)) N_(ldpc) N_(ldpc) _(—) _(parity) rate Q_(ldpc) PLS1342 1020 60 1080 4320 3240 1/4  36 PLS2 <1021 >1020 2100 2160 7200 50403/10 56

The LDPC parity punturing block can perform puncturing on the PLS1 dataand PLS 2 data.

When shortening is applied to the PLS1 data protection, some LDPC paritybits are punctured after LDPC encoding. Also, for the PLS2 dataprotection, the LDPC parity bits of PLS2 are punctured after LDPCencoding. These punctured bits are not transmitted.

The bit interleaver 6010 can interleave the each shortened and puncturedPLS1 data and PLS2 data.

The constellation mapper 6020 can map the bit ineterlaeved PLS1 data andPLS2 data onto constellations.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

The frame building block illustrated in FIG. 7 corresponds to anembodiment of the frame building block 1020 described with reference toFIG. 1.

Referring to FIG. 7, the frame building block can include a delaycompensation block 7000, a cell mapper 7010 and a frequency interleaver7020. Description will be given of each block of the frame buildingblock.

The delay compensation block 7000 can adjust the timing between the datapipes and the corresponding PLS data to ensure that they are co-timed atthe transmitter end. The PLS data is delayed by the same amount as datapipes are by addressing the delays of data pipes caused by the InputFormatting block and BICM block. The delay of the BICM block is mainlydue to the time interleaver. In-band signaling data carries informationof the next TI group so that they are carried one frame ahead of the DPsto be signaled. The Delay Compensating block delays in-band signalingdata accordingly.

The cell mapper 7010 can map PLS, EAC, FIC, DPs, auxiliary streams anddummy cells into the active carriers of the OFDM symbols in the frame.The basic function of the cell mapper 7010 is to map data cells producedby the TIs for each of the DPs, PLS cells, and EAC/FIC cells, if any,into arrays of active OFDM cells corresponding to each of the OFDMsymbols within a frame. Service signaling data (such as PSI (programspecific information)/SI) can be separately gathered and sent by a datapipe. The Cell Mapper operates according to the dynamic informationproduced by the scheduler and the configuration of the frame structure.Details of the frame will be described later.

The frequency interleaver 7020 can randomly interleave data cellsreceived from the cell mapper 7010 to provide frequency diversity. Also,the frequency interleaver 7020 can operate on very OFDM symbol paircomprised of two sequential OFDM symbols using a differentinterleaving-seed order to get maximum interleaving gain in a singleframe.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 8 illustrates an OFDM generation block according to an embodimentof the present invention.

The OFDM generation block illustrated in FIG. 8 corresponds to anembodiment of the OFDM generation block 1030 described with reference toFIG. 1.

The OFDM generation block modulates the OFDM carriers by the cellsproduced by the Frame Building block, inserts the pilots, and producesthe time domain signal for transmission. Also, this block subsequentlyinserts guard intervals, and applies PAPR (Peak-to-Average Power Radio)reduction processing to produce the final RF signal.

Referring to FIG. 8, the frame building block can include a pilot andreserved tone insertion block 8000, a 2D-eSFN encoding block 8010, anIFFT (Inverse Fast Fourier Transform) block 8020, a PAPR reduction block8030, a guard interval insertion block 8040, a preamble insertion block8050, other system insertion block 8060 and a DAC block 8070.Description will be given of each block of the frame building block.

The pilot and reserved tone insertion block 8000 can insert pilots andthe reserved tone.

Various cells within the OFDM symbol are modulated with referenceinformation, known as pilots, which have transmitted values known apriori in the receiver. The information of pilot cells is made up ofscattered pilots, continual pilots, edge pilots, FSS (frame signalingsymbol) pilots and FES (frame edge symbol) pilots. Each pilot istransmitted at a particular boosted power level according to pilot typeand pilot pattern. The value of the pilot information is derived from areference sequence, which is a series of values, one for eachtransmitted carrier on any given symbol. The pilots can be used forframe synchronization, frequency synchronization, time synchronization,channel estimation, and transmission mode identification, and also canbe used to follow the phase noise.

Reference information, taken from the reference sequence, is transmittedin scattered pilot cells in every symbol except the preamble, FSS andFES of the frame. Continual pilots are inserted in every symbol of theframe. The number and location of continual pilots depends on both theFFT size and the scattered pilot pattern. The edge carriers are edgepilots in every symbol except for the preamble symbol. They are insertedin order to allow frequency interpolation up to the edge of thespectrum. FSS pilots are inserted in FSS(s) and FES pilots are insertedin FES. They are inserted in order to allow time interpolation up to theedge of the frame.

The system according to an embodiment of the present invention supportsthe SFN network, where distributed MISO scheme is optionally used tosupport very robust transmission mode. The 2D-eSFN is a distributed MISOscheme that uses multiple TX antennas, each of which is located in thedifferent transmitter site in the SFN network.

The 2D-eSFN encoding block 8010 can process a 2D-eSFN processing todistorts the phase of the signals transmitted from multipletransmitters, in order to create both time and frequency diversity inthe SFN configuration. Hence, burst errors due to low flat fading ordeep-fading for a long time can be mitigated.

The IFFT block 8020 can modulate the output from the 2D-eSFN encodingblock 8010 using OFDM modulation scheme. Any cell in the data symbolswhich has not been designated as a pilot (or as a reserved tone) carriesone of the data cells from the frequency interleaver. The cells aremapped to OFDM carriers.

The PAPR reduction block 8030 can perform a PAPR reduction on inputsignal using various PAPR reduction algorithm in the time domain.

The guard interval insertion block 8040 can insert guard intervals andthe preamble insertion block 8050 can insert preamble in front of thesignal. Details of a structure of the preamble will be described later.The other system insertion block 8060 can multiplex signals of aplurality of broadcast transmission/reception systems in the time domainsuch that data of two or more different broadcast transmission/receptionsystems providing broadcast services can be simultaneously transmittedin the same RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc. Datarelated to respective broadcast services can be transmitted throughdifferent frames.

The DAC block 8070 can convert an input digital signal into an analogsignal and output the analog signal. The signal output from the DACblock 7800 can be transmitted through multiple output antennas accordingto the physical layer profiles. A Tx antenna according to an embodimentof the present invention can have vertical or horizontal polarity.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention cancorrespond to the apparatus for transmitting broadcast signals forfuture broadcast services, described with reference to FIG. 1.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention can includea synchronization & demodulation module 9000, a frame parsing module9010, a demapping & decoding module 9020, an output processor 9030 and asignaling decoding module 9040. A description will be given of operationof each module of the apparatus for receiving broadcast signals.

The synchronization & demodulation module 9000 can receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the apparatus for receivingbroadcast signals and carry out demodulation corresponding to a reverseprocedure of the procedure performed by the apparatus for transmittingbroadcast signals.

The frame parsing module 9100 can parse input signal frames and extractdata through which a service selected by a user is transmitted. If theapparatus for transmitting broadcast signals performs interleaving, theframe parsing module 9100 can carry out deinterleaving corresponding toa reverse procedure of interleaving. In this case, the positions of asignal and data that need to be extracted can be obtained by decodingdata output from the signaling decoding module 9400 to restorescheduling information generated by the apparatus for transmittingbroadcast signals.

The demapping & decoding module 9200 can convert the input signals intobit domain data and then deinterleave the same as necessary. Thedemapping & decoding module 9200 can perform demapping for mappingapplied for transmission efficiency and correct an error generated on atransmission channel through decoding. In this case, the demapping &decoding module 9200 can obtain transmission parameters necessary fordemapping and decoding by decoding the data output from the signalingdecoding module 9400.

The output processor 9300 can perform reverse procedures of variouscompression/signal processing procedures which are applied by theapparatus for transmitting broadcast signals to improve transmissionefficiency. In this case, the output processor 9300 can acquirenecessary control information from data output from the signalingdecoding module 9400. The output of the output processor 8300corresponds to a signal input to the apparatus for transmittingbroadcast signals and may be MPEG-TSs, IP streams (v4 or v6) and genericstreams.

The signaling decoding module 9400 can obtain PLS information from thesignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9100, demapping & decodingmodule 9200 and output processor 9300 can execute functions thereofusing the data output from the signaling decoding module 9400.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 10 shows an example configuration of the frame types and FRUs in asuper-frame. (a) shows a super frame according to an embodiment of thepresent invention, (b) shows FRU (Frame Repetition Unit) according to anembodiment of the present invention, (c) shows frames of variable PHYprofiles in the FRU and (d) shows a structure of a frame.

A super-frame may be composed of eight FRUs. The FRU is a basicmultiplexing unit for TDM of the frames, and is repeated eight times ina super-frame.

Each frame in the FRU belongs to one of the PHY profiles, (base,handheld, advanced) or FEE The maximum allowed number of the frames inthe FRU is four and a given PHY profile can appear any number of timesfrom zero times to four times in the FRU (e.g., base, base, handheld,advanced). PHY profile definitions can be extended using reserved valuesof the PHY_PROFILE in the preamble, if required.

The FEF part is inserted at the end of the FRU, if included. When theFEF is included in the FRU, the minimum number of FEFs is 8 in asuper-frame. It is not recommended that FEF parts be adjacent to eachother.

One frame is further divided into a number of OFDM symbols and apreamble. As shown in (d), the frame comprises a preamble, one or moreframe signaling symbols (FSS), normal data symbols and a frame edgesymbol (FES).

The preamble is a special symbol that enables fast Futurecast UTB systemsignal detection and provides a set of basic transmission parameters forefficient transmission and reception of the signal. The detaileddescription of the preamble will be will be described later.

The main purpose of the FSS(s) is to carry the PLS data. For fastsynchronization and channel estimation, and hence fast decoding of PLSdata, the FSS has more dense pilot pattern than the normal data symbol.The FES has exactly the same pilots as the FSS, which enablesfrequency-only interpolation within the FES and temporal interpolation,without extrapolation, for symbols immediately preceding the FES.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 11 illustrates the signaling hierarchy structure, which is splitinto three main parts: the preamble signaling data 11000, the PLS1 data11010 and the PLS2 data 11020. The purpose of the preamble, which iscarried by the preamble symbol in every frame, is to indicate thetransmission type and basic transmission parameters of that frame. ThePLS1 enables the receiver to access and decode the PLS2 data, whichcontains the parameters to access the DP of interest. The PLS2 iscarried in every frame and split into two main parts: PLS2-STAT data andPLS2-DYN data. The static and dynamic portion of PLS2 data is followedby padding, if necessary.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

Preamble signaling data carries 21 bits of information that are neededto enable the receiver to access PLS data and trace DPs within the framestructure. Details of the preamble signaling data are as follows:

PHY_PROFILE: This 3-bit field indicates the PHY profile type of thecurrent frame. The mapping of different PHY profile types is given inbelow table 5.

TABLE 5 Value PHY profile 000 Base profile 001 Handheld profile 010Advanced profiled 011~110 Reserved 111 FEF

FFT_SIZE: This 2 bit field indicates the FFT size of the current framewithin a frame-group, as described in below table 6.

TABLE 6 Value FFT size 00  8K FFT 01 16K FFT 10 32K FFT 11 Reserved

GI_FRACTION: This 3 bit field indicates the guard interval fractionvalue in the current super-frame, as described in below table 7.

TABLE 7 Value GI_FRACTION 000 ⅕  001 1/10 010 1/20 011 1/40 100 1/80 101  1/160 110~111 Reserved

EAC_FLAG: This 1 bit field indicates whether the EAC is provided in thecurrent frame. If this field is set to ‘1’, emergency alert service(EAS) is provided in the current frame. If this field set to ‘0’, EAS isnot carried in the current frame. This field can be switched dynamicallywithin a super-frame.

PILOT_MODE: This 1-bit field indicates whether the pilot mode is mobilemode or fixed mode for the current frame in the current frame-group. Ifthis field is set to ‘0’, mobile pilot mode is used. If the field is setto ‘1’, the fixed pilot mode is used.

PAPR_FLAG: This 1-bit field indicates whether PAPR reduction is used forthe current frame in the current frame-group. If this field is set tovalue ‘1’, tone reservation is used for PAPR reduction. If this field isset to ‘0’, PAPR reduction is not used.

FRU_CONFIGURE: This 3-bit field indicates the PHY profile typeconfigurations of the frame repetition units (FRU) that are present inthe current super-frame. All profile types conveyed in the currentsuper-frame are identified in this field in all preambles in the currentsuper-frame. The 3-bit field has a different definition for eachprofile, as show in below table 8.

TABLE 8 Current Current Current PHY_PROFILE = PHY_PROFILE = CurrentPHY_PROFILE = ‘001’ ‘010’ PHY_PROFILE = ‘000’ (base) (handheld)(advanced) ‘111’ (FEF) FRU_CONFIGURE = Only base Only handheld Onlyadvanced Only FEF 000 profile profile present profile present presentpresent FRU_CONFIGURE = Handheld profile Base profile Base profile Baseprofile 1XX present present present present FRU_CONFIGURE = AdvancedAdvanced Handheld profile Handheld profile X1X profile profile presentpresent present present FRU_CONFIGURE = FEF FEF FEF Advanced XX1 presentpresent present profile present

RESERVED: This 7-bit field is reserved for future use.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

PLS1 data provides basic transmission parameters including parametersrequired to enable the reception and decoding of the PLS2. As abovementioned, the PLS1 data remain unchanged for the entire duration of oneframe-group. The detailed definition of the signaling fields of the PLS1data are as follows:

PREAMBLE_DATA: This 20-bit field is a copy of the preamble signalingdata excluding the EAC_FLAG.

NUM_FRAME_FRU: This 2-bit field indicates the number of the frames perFRU.

PAYLOAD_TYPE: This 3-bit field indicates the format of the payload datacarried in the frame-group. PAYLOAD_TYPE is signaled as shown in table9.

TABLE 9 value Payload type 1XX TS stream is transmitted X1X IP stream istransmitted XX1 GS stream is transmitted

NUM_FSS: This 2-bit field indicates the number of FSS symbols in thecurrent frame.

SYSTEM_VERSION: This 8-bit field indicates the version of thetransmitted signal format. The SYSTEM_VERSION is divided into two 4-bitfields, which are a major version and a minor version.

Major version: The MSB four bits of SYSTEM_VERSION field indicate majorversion information. A change in the major version field indicates anon-backward-compatible change. The default value is ‘0000’. For theversion described in this standard, the value is set to ‘0000’.

Minor version: The LSB four bits of SYSTEM_VERSION field indicate minorversion information. A change in the minor version field isbackward-compatible.

CELL_ID: This is a 16-bit field which uniquely identifies a geographiccell in an ATSC network. An ATSC cell coverage area may consist of oneor more frequencies, depending on the number of frequencies used perFuturecast UTB system. If the value of the CELL_ID is not known orunspecified, this field is set to ‘0’.

NETWORK_ID: This is a 16-bit field which uniquely identifies the currentATSC network.

SYSTEM_ID: This 16-bit field uniquely identifies the Futurecast UTBsystem within the ATSC network. The Futurecast UTB system is theterrestrial broadcast system whose input is one or more input streams(TS, IP, GS) and whose output is an RF signal. The Futurecast UTB systemcarries one or more PHY profiles and FEF, if any. The same FuturecastUTB system may carry different input streams and use different RFfrequencies in different geographical areas, allowing local serviceinsertion. The frame structure and scheduling is controlled in one placeand is identical for all transmissions within a Futurecast UTB system.One or more Futurecast UTB systems may have the same SYSTEM_ID meaningthat they all have the same physical layer structure and configuration.

The following loop consists of FRU_PHY_PROFILE, FRU_FRAME_LENGTH,FRU_GI_FRACTION, and RESERVED which are used to indicate the FRUconfiguration and the length of each frame type. The loop size is fixedso that four PHY profiles (including a FEF) are signaled within the FRU.If NUM_FRAME_FRU is less than 4, the unused fields are filled withzeros.

FRU_PHY_PROFILE: This 3-bit field indicates the PHY profile type of the(i+1)^(th) (i is the loop index) frame of the associated FRU. This fielduses the same signaling format as shown in the table 8.

FRU_FRAME_LENGTH: This 2-bit field indicates the length of the(i+1)^(th) frame of the associated FRU. Using FRU_FRAME_LENGTH togetherwith FRU_GI_FRACTION, the exact value of the frame duration can beobtained.

FRU_GI_FRACTION: This 3-bit field indicates the guard interval fractionvalue of the (i+1)^(th) frame of the associated FRU. FRU_GI_FRACTION issignaled according to the table 7.

RESERVED: This 4-bit field is reserved for future use.

The following fields provide parameters for decoding the PLS2 data.

PLS2_FEC_TYPE: This 2-bit field indicates the FEC type used by the PLS2protection. The FEC type is signaled according to table 10. The detailsof the LDPC codes will be described later.

TABLE 10 Content PLS2 FEC type 00 4K-1/4 and 7K-3/10 LDPC codes 01~11Reserved

PLS2_MOD: This 3-bit field indicates the modulation type used by thePLS2. The modulation type is signaled according to table 11.

TABLE 11 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16 011 NUQ-64 100~111Reserved

PLS2_SIZE_CELL: This 15-bit field indicates C_(total) _(_) _(partial)_(_) _(block), the size (specified as the number of QAM cells) of thecollection of full coded blocks for PLS2 that is carried in the currentframe-group. This value is constant during the entire duration of thecurrent frame-group.

PLS2_STAT_SIZE_BIT: This 14-bit field indicates the size, in bits, ofthe PLS2-STAT for the current frame-group. This value is constant duringthe entire duration of the current frame-group.

PLS2_DYN_SIZE_BIT: This 14-bit field indicates the size, in bits, of thePLS2-DYN for the current frame-group. This value is constant during theentire duration of the current frame-group.

PLS2_REP_FLAG: This 1-bit flag indicates whether the PLS2 repetitionmode is used in the current frame-group. When this field is set to value‘1’, the PLS2 repetition mode is activated. When this field is set tovalue ‘0’, the PLS2 repetition mode is deactivated.

PLS2_REP_SIZE_CELL: This 15-bit field indicates C_(total) _(_)_(partial) _(_) _(block), the size (specified as the number of QAMcells) of the collection of partial coded blocks for PLS2 carried inevery frame of the current frame-group, when PLS2 repetition is used. Ifrepetition is not used, the value of this field is equal to 0. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_FEC_TYPE: This 2-bit field indicates the FEC type used forPLS2 that is carried in every frame of the next frame-group. The FECtype is signaled according to the table 10.

PLS2_NEXT_MOD: This 3-bit field indicates the modulation type used forPLS2 that is carried in every frame of the next frame-group. Themodulation type is signaled according to the table 11.

PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the PLS2repetition mode is used in the next frame-group. When this field is setto value ‘1’, the PLS2 repetition mode is activated. When this field isset to value ‘0’, the PLS2 repetition mode is deactivated.

PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicates C_(total) _(_)_(full) _(_) _(block), The size (specified as the number of QAM cells)of the collection of full coded blocks for PLS2 that is carried in everyframe of the next frame-group, when PLS2 repetition is used. Ifrepetition is not used in the next frame-group, the value of this fieldis equal to 0. This value is constant during the entire duration of thecurrent frame-group.

PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-STAT for the next frame-group. This value is constantin the current frame-group.

PLS2_NEXT_REP_DYN_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-DYN for the next frame-group. This value is constantin the current frame-group.

PLS2_AP_MODE: This 2-bit field indicates whether additional parity isprovided for PLS2 in the current frame-group. This value is constantduring the entire duration of the current frame-group. The below table12 gives the values of this field. When this field is set to ‘00’,additional parity is not used for the PLS2 in the current frame-group.

TABLE 12 Value PLS2-AP mode 00 AP is not provided 01 AP1 mode 10~11Reserved

PLS2_AP_SIZE_CELL: This 15-bit field indicates the size (specified asthe number of QAM cells) of the additional parity bits of the PLS2. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_AP_MODE: This 2-bit field indicates whether additional parityis provided for PLS2 signaling in every frame of next frame-group. Thisvalue is constant during the entire duration of the current frame-group.The table 12 defines the values of this field

PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates the size (specifiedas the number of QAM cells) of the additional parity bits of the PLS2 inevery frame of the next frame-group. This value is constant during theentire duration of the current frame-group.

RESERVED: This 32-bit field is reserved for future use.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS 1 signaling.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2-STAT data of the PLS2 data. The PLS2-STAT dataare the same within a frame-group, while the PLS2-DYN data provideinformation that is specific for the current frame.

The details of fields of the PLS2-STAT data are as follows:

FIC_FLAG: This 1-bit field indicates whether the FIC is used in thecurrent frame-group. If this field is set to ‘1’, the FIC is provided inthe current frame. If this field set to ‘0’, the FIC is not carried inthe current frame. This value is constant during the entire duration ofthe current frame-group.

AUX_FLAG: This 1-bit field indicates whether the auxiliary stream(s) isused in the current frame-group. If this field is set to ‘1’, theauxiliary stream is provided in the current frame. If this field set to‘0’, the auxiliary stream is not carried in the current frame. Thisvalue is constant during the entire duration of current frame-group.

NUM_DP: This 6-bit field indicates the number of DPs carried within thecurrent frame. The value of this field ranges from 1 to 64, and thenumber of DPs is NUM_DP+1.

DP_ID: This 6-bit field identifies uniquely a DP within a PHY profile.

DP_TYPE: This 3-bit field indicates the type of the DP. This is signaledaccording to the below table 13.

TABLE 13 Value DP Type 000 DP Type 1 001 DP Type 2 010~111 reserved

DP_GROUP_ID: This 8-bit field identifies the DP group with which thecurrent DP is associated. This can be used by a receiver to access theDPs of the service components associated with a particular service,which will have the same DP_GROUP_ID.

BASE_DP_ID: This 6-bit field indicates the DP carrying service signalingdata (such as PSI/SI) used in the Management layer. The DP indicated byBASE_DP_ID may be either a normal DP carrying the service signaling dataalong with the service data or a dedicated DP carrying only the servicesignaling data

DP_FEC_TYPE: This 2-bit field indicates the FEC type used by theassociated DP. The FEC type is signaled according to the below table 14.

TABLE 14 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10~11 Reserved

DP_COD: This 4-bit field indicates the code rate used by the associatedDP. The code rate is signaled according to the below table 15.

TABLE 15 Value Code rate 0000 5/15 0001 6/15 0010 7/15 0011 8/15 01009/15 0101 10/15  0110 11/15  0111 12/15  1000 13/15  1001~1111 Reserved

DP_MOD: This 4-bit field indicates the modulation used by the associatedDP. The modulation is signaled according to the below table 16.

TABLE 16 Value Modulation 0000 QPSK 0001 QAM-16 0010 NUQ-64 0011 NUQ-2560100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111 NUC-256 1000 NUC-10241001~1111 reserved

DP_SSD_FLAG: This 1-bit field indicates whether the SSD mode is used inthe associated DP. If this field is set to value ‘1’, SSD is used. Ifthis field is set to value ‘0’, SSD is not used.

The following field appears only if PHY_PROFILE is equal to ‘010’, whichindicates the advanced profile:

DP_MIMO: This 3-bit field indicates which type of MIMO encoding processis applied to the associated DP. The type of MIMO encoding process issignaled according to the table 17.

TABLE 17 Value MIMO encoding 000 FR-SM 001 FRFD-SM 010~111 reserved

DP_TI_TYPE: This 1-bit field indicates the type of time-interleaving. Avalue of ‘0’ indicates that one TI group corresponds to one frame andcontains one or more TI-blocks. A value of ‘1’ indicates that one TIgroup is carried in more than one frame and contains only one TI-block.

DP_TI_LENGTH: The use of this 2-bit field (the allowed values are only1, 2, 4, 8) is determined by the values set within the DP_TI_TYPE fieldas follows:

If the DP_TI_TYPE is set to the value ‘1’, this field indicates P_(I),the number of the frames to which each TI group is mapped, and there isone TI-block per TI group (N_(TI)=1). The allowed P_(I) values with2-bit field are defined in the below table 18.

If the DP_TI_TYPE is set to the value ‘0’, this field indicates thenumber of TI-blocks N_(TI) per TI group, and there is one TI group perframe (P_(I)=1). The allowed P_(I) values with 2-bit field are definedin the below table 18.

TABLE 18 2-bit field P_(I) N_(TI) 00 1 1 01 2 2 10 4 3 11 8 4

DP_FRAME_INTERVAL: This 2-bit field indicates the frame interval(I_(JUMP)) within the frame-group for the associated DP and the allowedvalues are 1, 2, 4, 8 (the corresponding 2-bit field is ‘00’, ‘01’,‘10’, or ‘11’, respectively). For DPs that do not appear every frame ofthe frame-group, the value of this field is equal to the intervalbetween successive frames. For example, if a DP appears on the frames 1,5, 9, 13, etc., this field is set to ‘4’. For DPs that appear in everyframe, this field is set to ‘1’.

DP_TI_BYPASS: This 1-bit field determines the availability of timeinterleaver. If time interleaving is not used for a DP, it is set to‘1’. Whereas if time interleaving is used it is set to ‘0’.

DP_FIRST_FRAME_IDX: This 5-bit field indicates the index of the firstframe of the super-frame in which the current DP occurs. The value ofDP_FIRST_FRAME_IDX ranges from 0 to 31

DP_NUM_BLOCK_MAX: This 10-bit field indicates the maximum value ofDP_NUM_BLOCKS for this DP. The value of this field has the same range asDP_NUM_BLOCKS.

DP_PAYLOAD_TYPE: This 2-bit field indicates the type of the payload datacarried by the given DP. DP_PAYLOAD_TYPE is signaled according to thebelow table 19.

TABLE 19 Value Payload Type 00 TS. 01 IP 10 GS 11 reserved

DP_INBAND_MODE: This 2-bit field indicates whether the current DPcarries in-band signaling information. The in-band signaling type issignaled according to the below table 20.

TABLE 20 Value In-band mode 00 In-band signaling is not carried. 01INBAND-PLS is carried only 10 INBAND-ISSY is carried only 11 INBAND-PLSand INBAND-ISSY are carried

DP_PROTOCOL_TYPE: This 2-bit field indicates the protocol type of thepayload carried by the given DP. It is signaled according to the belowtable 21 when input payload types are selected.

TABLE 21 If DP_PAYLOAD_TYPE If DP_PAYLOAD_TYPE If DP_PAYLOAD_TYPE ValueIs TS Is IP Is GS 00 MPEG2-TS IPv4 (Note) 01 Reserved IPv6 Reserved 10Reserved Reserved Reserved 11 Reserved Reserved Reserved

DP_CRC_MODE: This 2-bit field indicates whether CRC encoding is used inthe Input Formatting block. The CRC mode is signaled according to thebelow table 22.

TABLE 22 Value CRC mode 00 Not used 01 CRC-8 10 CRC-16 11 CRC-32

DNP_MODE: This 2-bit field indicates the null-packet deletion mode usedby the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). DNP_MODEis signaled according to the below table 23. If DP_PAYLOAD_TYPE is notTS (‘00’), DNP_MODE is set to the value ‘00’.

TABLE 23 Value Null-packet deletion mode 00 Not used 01 DNP-NORMAL 10DNP-OFFSET 11 reserved

ISSY_MODE: This 2-bit field indicates the ISSY mode used by theassociated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). The ISSY_MODE issignaled according to the below table 24 If DP_PAYLOAD_TYPE is not TS(‘00’), ISSY_MODE is set to the value ‘00’.

TABLE 24 Value ISSY mode 00 Not used 01 ISSY-UP 10 ISSY-BBF 11 reserved

HC_MODE_TS: This 2-bit field indicates the TS header compression modeused by the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). TheHC_MODE_TS is signaled according to the below table 25.

TABLE 25 Value Header compression mode 00 HC_MODE_TS 1 01 HC_MODE_TS 210 HC_MODE_TS 3 11 HC_MODE_TS 4

HC_MODE_IP: This 2-bit field indicates the IP header compression modewhen DP_PAYLOAD_TYPE is set to IP (‘01’). The HC_MODE_IP is signaledaccording to the below table 26.

TABLE 26 Value Header compression mode 00 No compression 01 HC_MODE_IP 110~11 reserved

PID: This 13-bit field indicates the PID number for TS headercompression when DP_PAYLOAD_TYPE is set to TS (‘00’) and HC_MODE_TS isset to ‘01’ or ‘10’.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if FIC_FLAG is equal to ‘1’:

FIC_VERSION: This 8-bit field indicates the version number of the FIC.

FIC_LENGTH_BYTE: This 13-bit field indicates the length, in bytes, ofthe FIC.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if AUX_FLAG is equal to ‘1’:

NUM_AUX: This 4-bit field indicates the number of auxiliary streams.Zero means no auxiliary streams are used.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use.

AUX_STREAM_TYPE: This 4-bit is reserved for future use for indicatingthe type of the current auxiliary stream.

AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future use forsignaling auxiliary streams.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 15 illustrates PLS2-DYN data of the PLS2 data. The values of thePLS2-DYN data may change during the duration of one frame-group, whilethe size of fields remains constant.

The details of fields of the PLS2-DYN data are as follows:

FRAME_INDEX: This 5-bit field indicates the frame index of the currentframe within the super-frame. The index of the first frame of thesuper-frame is set to ‘0’.

PLS_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration will change. The nextsuper-frame with changes in the configuration is indicated by the valuesignaled within this field. If this field is set to the value ‘0000’, itmeans that no scheduled change is foreseen: e.g., value ‘1’ indicatesthat there is a change in the next super-frame.

FIC_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration (i.e., the contents of theFIC) will change. The next super-frame with changes in the configurationis indicated by the value signaled within this field. If this field isset to the value ‘0000’, it means that no scheduled change is foreseen:e.g. value ‘0001’ indicates that there is a change in the nextsuper-frame.

RESERVED: This 16-bit field is reserved for future use.

The following fields appear in the loop over NUM_DP, which describe theparameters associated with the DP carried in the current frame.

DP_ID: This 6-bit field indicates uniquely the DP within a PHY profile.

DP_START: This 15-bit (or 13-bit) field indicates the start position ofthe first of the DPs using the DPU addressing scheme. The DP_START fieldhas differing length according to the PHY profile and FFT size as shownin the below table 27.

TABLE 27 DP_START field size PHY profile 64K 16K Base 13 bit 15 bitHandheld — 13 bit Advanced 13 bit 15 bit

DP_NUM_BLOCK: This 10-bit field indicates the number of FEC blocks inthe current TI group for the current DP. The value of DP_NUM_BLOCKranges from 0 to 1023

RESERVED: This 8-bit field is reserved for future use.

The following fields indicate the FIC parameters associated with theEAC.

EAC_FLAG: This 1-bit field indicates the existence of the EAC in thecurrent frame. This bit is the same value as the EAC_FLAG in thepreamble.

EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates the version numberof a wake-up indication.

If the EAC_FLAG field is equal to ‘1’, the following 12 bits areallocated for EAC_LENGTH_BYTE field. If the EAC_FLAG field is equal to‘0’, the following 12 bits are allocated for EAC_COUNTER.

EAC_LENGTH_BYTE: This 12-bit field indicates the length, in byte, of theEAC.

EAC_COUNTER: This 12-bit field indicates the number of the frames beforethe frame where the EAC arrives.

The following field appears only if the AUX_FLAG field is equal to ‘1’:

AUX_PRIVATE_DYN: This 48-bit field is reserved for future use forsignaling auxiliary streams. The meaning of this field depends on thevalue of AUX_STREAM_TYPE in the configurable PLS2-STAT.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS2.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

As above mentioned, the PLS, EAC, FIC, DPs, auxiliary streams and dummycells are mapped into the active carriers of the OFDM symbols in theframe. The PLS1 and PLS2 are first mapped into one or more FSS(s). Afterthat, EAC cells, if any, are mapped immediately following the PLS field,followed next by FIC cells, if any. The DPs are mapped next after thePLS or EAC, FIC, if any. Type 1 DPs follows first, and Type 2 DPs next.The details of a type of the DP will be described later. In some case,DPs may carry some special data for EAS or service signaling data. Theauxiliary stream or streams, if any, follow the DPs, which in turn arefollowed by dummy cells. Mapping them all together in the abovementioned order, i.e. PLS, EAC, FIC, DPs, auxiliary streams and dummydata cells exactly fill the cell capacity in the frame.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

PLS cells are mapped to the active carriers of FSS(s). Depending on thenumber of cells occupied by PLS, one or more symbols are designated asFSS(s), and the number of FSS(s) N_(FSS) is signaled by NUM_FSS in PLS1.The FSS is a special symbol for carrying PLS cells. Since robustness andlatency are critical issues in the PLS, the FSS(s) has higher density ofpilots allowing fast synchronization and frequency-only interpolationwithin the FSS.

PLS cells are mapped to active carriers of the N_(FSS) FSS(s) in atop-down manner as shown in an example in FIG. 17. The PLS1 cells aremapped first from the first cell of the first FSS in an increasing orderof the cell index. The PLS2 cells follow immediately after the last cellof the PLS1 and mapping continues downward until the last cell index ofthe first FSS. If the total number of required PLS cells exceeds thenumber of active carriers of one FSS, mapping proceeds to the next FSSand continues in exactly the same manner as the first FSS.

After PLS mapping is completed, DPs are carried next. If EAC, FIC orboth are present in the current frame, they are placed between PLS and“normal” DPs.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

EAC is a dedicated channel for carrying EAS messages and links to theDPs for EAS. EAS support is provided but EAC itself may or may not bepresent in every frame. EAC, if any, is mapped immediately after thePLS2 cells. EAC is not preceded by any of the FIC, DPs, auxiliarystreams or dummy cells other than the PLS cells. The procedure ofmapping the EAC cells is exactly the same as that of the PLS.

The EAC cells are mapped from the next cell of the PLS2 in increasingorder of the cell index as shown in the example in FIG. 18. Depending onthe EAS message size, EAC cells may occupy a few symbols, as shown inFIG. 18.

EAC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required EAC cells exceeds the number of remainingactive carriers of the last FSS mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol, which has more activecarriers than a FSS.

After EAC mapping is completed, the FIC is carried next, if any exists.If FIC is not transmitted (as signaled in the PLS2 field), DPs followimmediately after the last cell of the EAC.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

(a) shows an example mapping of FIC cell without EAC and (b) shows anexample mapping of FIC cell with EAC.

FIC is a dedicated channel for carrying cross-layer information toenable fast service acquisition and channel scanning. This informationprimarily includes channel binding information between DPs and theservices of each broadcaster. For fast scan, a receiver can decode FICand obtain information such as broadcaster ID, number of services, andBASE_DP_ID. For fast service acquisition, in addition to FIC, base DPcan be decoded using BASE_DP_ID. Other than the content it carries, abase DP is encoded and mapped to a frame in exactly the same way as anormal DP. Therefore, no additional description is required for a baseDP. The FIC data is generated and consumed in the Management Layer. Thecontent of FIC data is as described in the Management Layerspecification.

The FIC data is optional and the use of FIC is signaled by the FIC_FLAGparameter in the static part of the PLS2. If FIC is used, FIC_FLAG isset to ‘1’ and the signaling field for FIC is defined in the static partof PLS2. Signaled in this field are FIC_VERSION, and FIC_LENGTH_BYTE.FIC uses the same modulation, coding and time interleaving parameters asPLS2. FIC shares the same signaling parameters such as PLS2_MOD andPLS2_FEC. FIC data, if any, is mapped immediately after PLS2 or EAC ifany. FIC is not preceded by any normal DPs, auxiliary streams or dummycells. The method of mapping FIC cells is exactly the same as that ofEAC which is again the same as PLS.

Without EAC after PLS, FIC cells are mapped from the next cell of thePLS2 in an increasing order of the cell index as shown in an example in(a). Depending on the FIC data size, FIC cells may be mapped over a fewsymbols, as shown in (b).

FIC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required FIC cells exceeds the number of remainingactive carriers of the last FSS, mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol which has more activecarriers than a FSS.

If EAS messages are transmitted in the current frame, EAC precedes FIC,and FIC cells are mapped from the next cell of the EAC in an increasingorder of the cell index as shown in (b).

After FIC mapping is completed, one or more DPs are mapped, followed byauxiliary streams, if any, and dummy cells.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

(a) shows type 1 DP and (b) shows type 2 DP.

After the preceding channels, i.e., PLS, EAC and FIC, are mapped, cellsof the DPs are mapped. A DP is categorized into one of two typesaccording to mapping method:

Type 1 DP: DP is mapped by TDM

Type 2 DP: DP is mapped by FDM

The type of DP is indicated by DP_TYPE field in the static part of PLS2.FIG. 20 illustrates the mapping orders of Type 1 DPs and Type 2 DPs.Type 1 DPs are first mapped in the increasing order of cell index, andthen after reaching the last cell index, the symbol index is increasedby one. Within the next symbol, the DP continues to be mapped in theincreasing order of cell index starting from p=0. With a number of DPsmapped together in one frame, each of the Type 1 DPs are grouped intime, similar to TDM multiplexing of DPs.

Type 2 DPs are first mapped in the increasing order of symbol index, andthen after reaching the last OFDM symbol of the frame, the cell indexincreases by one and the symbol index rolls back to the first availablesymbol and then increases from that symbol index. After mapping a numberof DPs together in one frame, each of the Type 2 DPs are grouped infrequency together, similar to FDM multiplexing of DPs.

Type 1 DPs and Type 2 DPs can coexist in a frame if needed with onerestriction; Type 1 DPs always precede Type 2 DPs. The total number ofOFDM cells carrying Type 1 and Type 2 DPs cannot exceed the total numberof OFDM cells available for transmission of DPs:

D _(DP1) +D _(DP2) ≦D _(DP)  [Expression 2]

where D_(DPI) is the number of OFDM cells occupied by Type 1 DPs,D_(DP2) is the number of cells occupied by Type 2 DPs. Since PLS, EAC,FIC are all mapped in the same way as Type 1 DP, they all follow “Type 1mapping rule”. Hence, overall, Type 1 mapping always precedes Type 2mapping.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

(a) shows an addressing of OFDM cells for mapping type 1 DPs and (b)shows an addressing of OFDM cells for mapping for type 2 DPs.

Addressing of OFDM cells for mapping Type 1 DPs (0, . . . , D_(DP1)−1)is defined for the active data cells of Type 1 DPs. The addressingscheme defines the order in which the cells from the TIs for each of theType 1 DPs are allocated to the active data cells. It is also used tosignal the locations of the DPs in the dynamic part of the PLS2.

Without EAC and FIC, address 0 refers to the cell immediately followingthe last cell carrying PLS in the last FSS. If EAC is transmitted andFIC is not in the corresponding frame, address 0 refers to the cellimmediately following the last cell carrying EAC. If FIC is transmittedin the corresponding frame, address 0 refers to the cell immediatelyfollowing the last cell carrying FIC. Address 0 for Type 1 DPs can becalculated considering two different cases as shown in (a). In theexample in (a), PLS, EAC and FIC are assumed to be all transmitted.Extension to the cases where either or both of EAC and FIC are omittedis straightforward. If there are remaining cells in the FSS aftermapping all the cells up to FIC as shown on the left side of (a).

Addressing of OFDM cells for mapping Type 2 DPs (0, . . . , D_(DP2)−1)is defined for the active data cells of Type 2 DPs. The addressingscheme defines the order in which the cells from the TIs for each of theType 2 DPs are allocated to the active data cells. It is also used tosignal the locations of the DPs in the dynamic part of the PLS2.

Three slightly different cases are possible as shown in (b). For thefirst case shown on the left side of (b), cells in the last FSS areavailable for Type 2 DP mapping. For the second case shown in themiddle, FIC occupies cells of a normal symbol, but the number of FICcells on that symbol is not larger than C_(FSS). The third case, shownon the right side in (b), is the same as the second case except that thenumber of FIC cells mapped on that symbol exceeds C_(FSS).

The extension to the case where Type 1 DP(s) precede Type 2 DP(s) isstraightforward since PLS, EAC and FIC follow the same “Type 1 mappingrule” as the Type 1 DP(s).

A data pipe unit (DPU) is a basic unit for allocating data cells to a DPin a frame.

A DPU is defined as a signaling unit for locating DPs in a frame. A CellMapper 7010 may map the cells produced by the TIs for each of the DPs. ATime interleaver 5050 outputs a series of TI-blocks and each TI-blockcomprises a variable number of XFECBLOCKs which is in turn composed of aset of cells. The number of cells in an XFECBLOCK, N_(cells), isdependent on the FECBLOCK size, N_(ldpc), and the number of transmittedbits per constellation symbol. A DPU is defined as the greatest commondivisor of all possible values of the number of cells in a XFECBLOCK,N_(cells), supported in a given PHY profile. The length of a DPU incells is defined as L_(DPU). Since each PHY profile supports differentcombinations of FECBLOCK size and a different number of bits perconstellation symbol, L_(DPU) is defined on a PHY profile basis.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention before bit interleaving. As above mentioned, Data FECencoder may perform the FEC encoding on the input BBF to generateFECBLOCK procedure using outer coding (BCH), and inner coding (LDPC).The illustrated FEC structure corresponds to the FECBLOCK. Also, theFECBLOCK and the FEC structure have same value corresponding to a lengthof LDPC codeword.

The BCH encoding is applied to each BBF (K_(bch) bits), and then LDPCencoding is applied to BCH-encoded BBF (K_(ldpc) bits=N_(bch) bits) asillustrated in FIG. 22.

The value of N_(ldpc) is either 64800 bits (long FECBLOCK) or 16200 bits(short FECBLOCK).

The below table 28 and table 29 show FEC encoding parameters for a longFECBLOCK and a short FECBLOCK, respectively.

TABLE 28 BCH error LDPC correction Rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 64800 21600 21408 12 192 6/15 2592025728 7/15 30240 30048 8/15 34560 34368 9/15 38880 38688 10/15  4320043008 11/15  47520 47328 12/15  51840 51648 13/15  56160 55968

TABLE 29 BCH error LDPC correction Rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 16200 5400 5232 12 168 6/15 6480 63127/15 7560 7392 8/15 8640 8472 9/15 9720 9552 10/15  10800 10632 11/15 11880 11712 12/15  12960 12792 13/15  14040 13872

The details of operations of the BCH encoding and LDPC encoding are asfollows:

A 12-error correcting BCH code is used for outer encoding of the BBF.The BCH generator polynomial for short FECBLOCK and long FECBLOCK areobtained by multiplying together all polynomials.

LDPC code is used to encode the output of the outer BCH encoding. Togenerate a completed B_(ldpc) (FECBLOCK), P_(ldpc) (parity bits) isencoded systematically from each I_(ldpc) (BCH-encoded BBF), andappended to I_(ldpc). The completed B_(ldpc), (FECBLOCK) are expressedas follow Expression.

B _(ldpc) =[I _(ldpc) P _(ldpc) ]==[i ₀ ,i ₁ , . . . i _(K) _(ldpc) ₋₁,p ₀ ,p ₁ , . . . p _(N) _(ldpc) _(-K) _(ldpc) ₋₁][Expression 3]

The parameters for long FECBLOCK and short FECBLOCK are given in theabove table 28 and 29, respectively.

The detailed procedure to calculate N_(ldpc)−K_(ldpc) parity bits forlong FECBLOCK, is as follows:

1) Initialize the parity bits,

p ₀ =p ₁ =p ₂ = . . . =p _(N) _(ldcp) _(-K) _(ldpc) ₋₁[Expression 4]

2) Accumulate the first information bit—i₀, at parity bit addressesspecified in the first row of an addresses of parity check matrix. Thedetails of addresses of parity check matrix will be described later. Forexample, for rate 13/15:

p ₉₈₃ =p ₉₈₃ ⊕i ₀ p ₂₈₁₅ =p ₂₈₁₅ ⊕i ₀

p ₄₈₃₇ =p ₄₈₃₇ ⊕i ₀ p ₄₉₈₉ =p ₄₉₈₉ ⊕i ₀

p ₆₁₃₈ =p ₆₁₃₈ ⊕i ₀ p ₆₄₅₈ =p ₆₄₅₈ ⊕i ₀

p ₆₉₂₁ =p ₆₉₂₁ ⊕i ₀ p ₆₉₇₄ =p ₆₉₇₄ ⊕i ₀

p ₇₅₇₂ =p ₇₅₇₂ ⊕i ₀ p ₈₂₆₀ =p ₈₂₆₀ ⊕i ₀

p ₈₄₉₆ =p ₈₄₉₆ ⊕i ₀  [Expression 5]

3) For the next 359 information bits, i_(s), s=1, 2, . . . , 359accumulate i_(s) at parity bit addresses using following Expression.

{x+(s mod 360)×Q _(ldpc)} mod(N _(ldpc) −K _(ldpc))  [Expression 6]

where x denotes the address of the parity bit accumulator correspondingto the first bit i₀, and Q_(ldpc) is a code rate dependent constantspecified in the addresses of parity check matrix. Continuing with theexample, Q_(ldpc)=24 for rate 13/15, so for information bit i₁, thefollowing operations are performed:

p ₁₀₀₇ =p ₁₀₀₇ ⊕i ₁ p ₂₈₃₉ =p ₂₈₃₉ ⊕i ₁

p ₄₈₆₁ =p ₄₈₆₁ ⊕i ₁ p ₅₀₁₃ =p ₅₀₁₃ ⊕i ₁

p ₆₁₆₂ =p ₆₁₆₂ ⊕i ₁ p ₆₄₈₂ =p ₆₄₈₂ ⊕i ₁

p ₆₉₄₅ =p ₆₉₄₅ ⊕i ₁ p ₆₉₉₈ =p ₆₉₉₈ ⊕i ₁

p ₇₅₉₆ =p ₇₅₉₅ ⊕i ₁ p ₈₂₈₄ =p ₈₂₈₄ ⊕i ₁

p ₈₅₂₀ =p ₈₅₂₀ ⊕i ₁  [Expression 7]

4) For the 361^(st) information bit i₃₆₀, the addresses of the paritybit accumulators are given in the second row of the addresses of paritycheck matrix. In a similar manner the addresses of the parity bitaccumulators for the following 359 information bits i_(s), s=361, 362, .. . , 719 are obtained using the Expression 6, where x denotes theaddress of the parity bit accumulator corresponding to the informationbit i₃₆₀, i.e., the entries in the second row of the addresses of paritycheck matrix.

5) In a similar manner, for every group of 360 new information bits, anew row from addresses of parity check matrixes used to find theaddresses of the parity bit accumulators.

After all of the information bits are exhausted, the final parity bitsare obtained as follows:

6) Sequentially perform the following operations starting with i=1

p _(i) =p _(i) ⊕p _(i-1) , i=1,2, . . . ,N _(ldpc)-K_(ldpc)−1[Expression 8]

where final content of p_(i), i=0, 1, . . . N_(ldpc)-K_(ldpc)−1 is equalto the parity bit p_(i).

TABLE 30 Code Rate Q_(ldpc) 5/15 120 6/15 108 7/15 96 8/15 84 9/15 7210/15  60 11/15  48 12/15  36 13/15  24

This LDPC encoding procedure for a short FECBLOCK is in accordance witht LDPC encoding procedure for the long FECBLOCK, except replacing thetable 30 with table 31, and replacing the addresses of parity checkmatrix for the long FECBLOCK with the addresses of parity check matrixfor the short FECBLOCK.

TABLE 31 Code Rate Q_(ldpc) 5/15 30 6/15 27 7/15 24 8/15 21 9/15 1810/15  15 11/15  12 12/15  9 13/15  6

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

The outputs of the LDPC encoder are bit-interleaved, which consists ofparity interleaving followed by Quasi-Cyclic Block (QCB) interleavingand inner-group interleaving.

(a) shows Quasi-Cyclic Block (QCB) interleaving and (b) showsinner-group interleaving.

The FECBLOCK may be parity interleaved. At the output of the parityinterleaving, the LDPC codeword consists of 180 adjacent QC blocks in along FECBLOCK and 45 adjacent QC blocks in a short FECBLOCK. Each QCblock in either a long or short FECBLOCK consists of 360 bits. Theparity interleaved LDPC codeword is interleaved by QCB interleaving. Theunit of QCB interleaving is a QC block. The QC blocks at the output ofparity interleaving are permutated by QCB interleaving as illustrated inFIG. 23, where N_(cells)=64800/η_(mod) or 16200/η_(mod) according to theFECBLOCK length. The QCB interleaving pattern is unique to eachcombination of modulation type and LDPC code rate.

After QCB interleaving, inner-group interleaving is performed accordingto modulation type and order (η_(mod)) which is defined in the belowtable 32. The number of QC blocks for one inner-group, N_(QCB) _(_)_(IG) is also defined.

TABLE 32 Modulation type η_(mod) N_(QCB) _(—) _(IG) QAM-16 4 2 NUC-16 44 NUQ-64 6 3 NUC-64 6 6 NUQ-256 8 4 NUC-256 8 8 NUQ-1024 10 5 NUC-102410 10

The inner-group interleaving process is performed with N_(QCB) _(_)_(IG) QC blocks of the QCB interleaving output. Inner-group interleavinghas a process of writing and reading the bits of the inner-group using360 columns and N_(QCB) _(_) _(IG) rows. In the write operation, thebits from the QCB interleaving output are written row-wise. The readoperation is performed column-wise to read out m bits from each row,where m is equal to 1 for NUC and 2 for NUQ.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

(a) shows a cell-word demultiplexing for 8 and 12 bpcu MIMO and (b)shows a cell-word demultiplexing for 10 bpcu MIMO.

Each cell word (c_(0,l), c_(1,l) . . . c_(η mod-1,l)) of the bitinterleaving output is demultiplexed into (d_(1,0,m), d_(1,1,m) . . . ,d_(1,η mod-1,m)) and (d_(2,0,m), d_(2,1,m) . . . , d_(2,η mod-1,m)) asshown in (a), which describes the cell-word demultiplexing process forone XFECBLOCK.

For the 10 bpcu MIMO case using different types of NUQ for MIMOencoding, the Bit Interleaver for NUQ-1024 is re-used. Each cell word(c_(0,l), c_(1,l), . . . , c_(9,l)) of the Bit Interleaver output isdemultiplexed into (d_(1,0,m), d_(1,1,m) . . . , d_(1,3,m)) and(d_(2,0,m), d_(2,1,m) . . . , d_(2,5,m)), as shown in (b).

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

(a) to (c) show examples of TI mode.

The time interleaver operates at the DP level. The parameters of timeinterleaving (TI) may be set differently for each DP.

The following parameters, which appear in part of the PLS2-STAT data,configure the TI:

DP_TI_TYPE (allowed values: 0 or 1): Represents the TI mode; ‘0’indicates the mode with multiple TI blocks (more than one TI block) perTI group. In this case, one TI group is directly mapped to one frame (nointer-frame interleaving). ‘1’ indicates the mode with only one TI blockper TI group. In this case, the TI block may be spread over more thanone frame (inter-frame interleaving).

DP_TI_LENGTH: If DP_TI_TYPE=‘0’, this parameter is the number of TIblocks N_(TI) per TI group. For DP_TI_TYPE=‘1’, this parameter is thenumber of frames P_(I) spread from one TI group.

DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): Represents the maximumnumber of XFECBLOCKs per TI group.

DP_FRAME_INTERVAL (allowed values: 1, 2, 4, 8): Represents the number ofthe frames L_(JUMP) between two successive frames carrying the same DPof a given PHY profile.

DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving is not usedfor a DP, this parameter is set to ‘1’. It is set to ‘0’ if timeinterleaving is used.

Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN data is usedto represent the number of XFECBLOCKs carried by one TI group of the DP.

When time interleaving is not used for a DP, the following TI group,time interleaving operation, and TI mode are not considered. However,the Delay Compensation block for the dynamic configuration informationfrom the scheduler will still be required. In each DP, the XFECBLOCKsreceived from the SSD/MIMO encoding are grouped into TI groups. That is,each TI group is a set of an integer number of XFECBLOCKs and willcontain a dynamically variable number of XFECBLOCKs. The number ofXFECBLOCKs in the TI group of index n is denoted by N_(xBLOCK) _(_)_(Group)(n) and is signaled as DP_NUM_BLOCK in the PLS2-DYN data. Notethat N_(xBLOCK) _(_) _(Group)(n) may vary from the minimum value of 0 tothe maximum value N_(xBLOCK) _(_) _(Group) _(_) _(MAX)(corresponding toDP_NUM_BLOCK_MAX) of which the largest value is 1023.

Each TI group is either mapped directly onto one frame or spread overP_(I) frames. Each TI group is also divided into more than one TI blocks(N_(TI)), where each TI block corresponds to one usage of timeinterleaver memory. The TI blocks within the TI group may containslightly different numbers of XFECBLOCKs. If the TI group is dividedinto multiple TI blocks, it is directly mapped to only one frame. Thereare three options for time interleaving (except the extra option ofskipping the time interleaving) as shown in the below table 33.

TABLE 33 Modes Descriptions Option-1 Each TI group contains one TI blockand is mapped directly to one frame as shown in (a). This option issignaled in the PLS2-STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH =‘1’(N_(TI) = 1). Option-2 Each TI group contains one TI block and ismapped to more than one frame. (b) shows an example, where one TI groupis mapped to two frames, i.e., DP_TI_LENGTH = ‘2’ (P_(I) = 2) andDP_FRAME_INTERVAL (I_(JUMP) = 2). This provides greater time diversityfor low data-rate services. This option is signaled in the PLS2-STAT byDP_TI_TYPE = ‘1’. Option-3 Each TI group is divided into multiple TIblocks and is mapped directly to one frame as shown in (c). Each TIblock may use full TI memory, so as to provide the maximum bit-rate fora DP. This option is signaled in the PLS2-STAT signaling by DP_TI_TYPE =‘0’ and DP_TI_LENGTH = N_(TI), while P_(I) = 1.

In each DP, the TI memory stores the input XFECBLOCKs (output XFECBLOCKsfrom the SSD/MIMO encoding block). Assume that input XFECBLOCKs aredefined as

(d_(n, s, 0, 0), d_(n, s, 0, 1), ⋯  , d_(n, s, 0, N_(cells) − 1), d_(n, s, 1, 0), ⋯  , d_(n, s, 1, N_(cells) − 1), ⋯  , d_(n, s, N_(xBLOCK_TI)(n, s) − 1, 0), ⋯  , d_(n, s, N_(xBLOCK_TI)(n, s) − 1, N_(cells) − 1)),

where d_(n,s,r,q) is the qth cell of the rth XFECBLOCK in the sth TIblock of the nth TI group and represents the outputs of SSD and MIMOencodings as follows.

$d_{n,s,r,q} = \left\{ {\begin{matrix}{f_{n,s,r,q},} & {{theoutputofSSD}\mspace{14mu} \ldots \mspace{14mu} {encoding}} \\{g_{n,s,r,q},} & {{theoutputof}\; {MIMOencoding}}\end{matrix}.} \right.$

In addition, assume that output XFECBLOCKs from the time interleaver aredefined as

(h_(n, s, 0), h_(n, s, 1), ⋯  , h_(n, s, i), ⋯  , h_(n, s, N_(xBLOCK_TI)(n, s) × N_(cells) − 1)),

where h_(n,s,i) is the ith output cell (for i=0, . . . , N_(xBLOCK) _(_)_(TI) (n,s)×N_(cells)−1) in the sth TI block of the nth TI group.

Typically, the time interleaver will also act as a buffer for DP dataprior to the process of frame building. This is achieved by means of twomemory banks for each DP. The first TI-block is written to the firstbank. The second TI-block is written to the second bank while the firstbank is being read from and so on.

The TI is a twisted row-column block interleaver. For the sth TI blockof the nth TI group, the number of rows N_(r) of a TI memory is equal tothe number of cells N_(cells), i.e., N_(r)=N_(cells), while the numberof columns N_(c) is equal to the number N_(xBLOCK) _(_) _(TI)(n,s).

FIG. 26 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

shows a writing operation in the time interleaver and (b) shows areading operation in the time interleaver The first XFECBLOCK is writtencolumn-wise into the first column of the TI memory, and the secondXFECBLOCK is written into the next column, and so on as shown in (a).Then, in the interleaving array, cells are read out diagonal-wise.During diagonal-wise reading from the first row (rightwards along therow beginning with the left-most column) to the last row, N_(r) cellsare read out as shown in (b). In detail, assuming z_(n,s,i) (i=0, . . ., N_(r)N_(c)) as the TI memory cell position to be read sequentially,the reading process in such an interleaving array is performed bycalculating the row index R_(n,s,i), the column index C_(n,s,i), and theassociated twisting parameter T_(n,s,i) as follows expression.

$\begin{matrix}{{{GENERATE}\; \left( {R_{n,s,i},C_{n,s,i}} \right)} = \left\{ {{R_{n,s,i} = {{mod}\; \left( {i,N_{r}} \right)}},{T_{n,s,i} = {{mod}\; \left( {{S_{shift} \times R_{n,s,i}},N_{c}} \right)}},{C_{n,s,i} = {{mod}\; \left( {{T_{n,s,i} + \left\lfloor \frac{i}{N_{r}} \right\rfloor},N_{c}} \right)}}} \right\}} & \left\lbrack {{Expression}\mspace{14mu} 9} \right\rbrack\end{matrix}$

where S_(shift) is a common shift value for the diagonal-wise readingprocess regardless of N_(xBLOCK) _(_) _(TI)(n,s), and it is determinedby N_(xBLOCK) _(_) _(TI) _(_) _(MAX) given in the PLS2-STAT as followsexpression.

                                   [Expression  10]${for}\mspace{14mu} \left\{ {\begin{matrix}{{N_{{xBLOCK\_ TI}{\_ MAX}}^{\prime} = {N_{{xBLOCK\_ TI}{\_ MAX}} + 1}},} & {{{if}\mspace{14mu} N_{{xBLOCK\_ TI}{\_ MAX}}{mod}\; 2} = 0} \\{{N_{{xBLOCK\_ TI}{\_ MAX}}^{\prime} = N_{{xBLOCK\_ TI}{\_ MAX}}},} & {{{if}\mspace{14mu} N_{{xBLOCK\_ TI}{\_ MAX}}{mod}\; 2} = 1}\end{matrix},\mspace{20mu} {S_{shift} = \frac{N_{{xBLOCK\_ TI}{\_ MAX}}^{\prime} - 1}{2}}} \right.$

As a result, the cell positions to be read are calculated by acoordinate as z_(n,s,i)=N_(r)C_(n,s,i)+R_(n,s,i).

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

More specifically, FIG. 27 illustrates the interleaving array in the TImemory for each TI group, including virtual XFECBLOCKs when N_(xBLOCK)_(_) _(TI)(0,0)=3, N_(xBLOCK) _(_) _(TI) (1,0)=6, N_(xBLOCK) _(_)_(TI)(2,0)=5.

The variable number N_(xBLOCK) _(_) _(TI)(n,s)=N_(r) will be less thanor equal to N_(xBLOCK) _(_) _(TI) _(_) _(MAX). Thus, in order to achievea single-memory deinterleaving at the receiver side, regardless ofN_(xBLOCK) _(_) _(TI)(n,s), the interleaving array for use in a twistedrow-column block interleaver is set to the size ofN_(r)×N_(c)=N_(cells)×N_(xBLOCK) _(_) _(TI) _(_) _(MAX) by inserting thevirtual XFECBLOCKs into the TI memory and the reading process isaccomplished as follow expression.

[Expression 11] p = 0; for i = 0; i < N_(cells)N′_(xBLOCK) _(—) _(TI)_(—) _(MAX); i = i + 1 {GENERATE (R_(n,s,i), C_(n,s,i)); V_(i) =N_(r)C_(n,s,j) + R_(n,s,j)  if V_(i) < N_(cells)N_(xBLOCK TI)(n,s)  {  Z_(n,s,p) = V_(i); p = p + 1;   } }

The number of TI groups is set to 3. The option of time interleaver issignaled in the PLS2-STAT data by DP_TI_TYPE=‘0’. DP_FRAME_INTERVAL=‘1’,and DP_TI_LENGTH=‘1’, i.e., N_(TI)=1, I_(JUMP)=1, and P_(I)=1. Thenumber of XFECBLOCKs, each of which has N_(cells)=30 cells, per TI groupis signaled in the PLS2-DYN data by N_(xBLOCK) _(_) _(TI)(0,0)=3,N_(xBLOCK) _(_) _(TI)(1,0)=6, and NN_(xBLOCK) _(_) _(TI)(2,0)=5,respectively. The maximum number of XFECBLOCK is signaled in thePLS2-STAT data by NN_(xBLOCK) _(_) _(Group) _(_) _(MAX), which leads to└N_(xBLOCK) _(_) _(Group) _(_) _(MAX)/N_(TI)┘=N_(xBLOCK) _(_) _(TI) _(_)_(MAX)=6.

FIG. 28 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

More specifically FIG. 28 shows a diagonal-wise reading pattern fromeach interleaving array with parameters of N′_(xBLOCK) _(_) _(TI) _(_)_(MAX)=7 and S_(shift)=(7−1)/2=3. Note that in the reading process shownas pseudocode above, if V_(i)≧N_(cells)N_(xBLOCK) _(_) _(TI)(n,s) thevalue of V_(i) is skipped and the next calculated value of V_(i) isused.

FIG. 29 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 29 illustrates the interleaved XFECBLOCKs from each interleavingarray with parameters of N′_(xBLOCK) _(_) _(TI) _(_) _(MAX)=7 andS_(shift)=3.

FIG. 30 is a view illustrating a coding & modulation module according toanother embodiment of the present invention.

As described above, a constellation mapper allocates input bit words toone constellation. In this case, a rotation & Q-delay block may beadditionally used. The rotation & Q-delay block may rotate inputconstellations based on rotation angles, divide the same into in-phase(I) components and quadrature-phase (Q) components, and then delay onlythe Q components by an arbitrary value. After that, newly paired Icomponents and Q components are remapped to new constellations. Theconstellation mapper and the rotation & Q-delay block may be omitted ormay be replaced by other blocks having the same or similar functions.

As described above, a cell interleaver randomly mixes and outputs cellscorresponding to one FEC block in such a manner that the cellscorresponding to each FEC block are output in a different order fromcells corresponding to another FEC block. The cell interleaver may beomitted or may be replaced by another block having the same or similarfunction.

In the coding & modulation module according to another embodiment of thepresent invention, the shaded blocks are modified from theabove-described coding & modulation module.

The coding & modulation module according to another embodiment of thepresent invention may perform periodic-random UQ interleaving. Theperiodic-random UQ interleaving technology may correspond to operationsof the Q-delay block and the cell interleaver in this figure. Inaddition, according to an embodiment, when cell interleaving is omitted,periodic-random UQ interleaving may be performed before timeinterleaving. Furthermore, according to another embodiment, when thecell interleaver is omitted, a time interleaver may performperiodic-random I/Q interleaving. In this case, the time interleaver mayperform only the periodic-random I/Q interleaving operation, or performthe periodic-random I/Q interleaving operation and the above-describedoperation of the time interleaver in the next-generation broadcastsystem.

Overall, periodic-random I/Q interleaving may divide inputconstellations rotated based on rotation angles into I components and Qcomponents, delay only the Q components by an arbitrary value, and thenperiodically and randomly mix the components. Periodic-random I/Qinterleaving may be performed by one block differently from the aboveblock diagram. In addition, as described above, periodic-random I/Qinterleaving may be a technology performed by the time interleaveraccording to an embodiment. A detailed description of the operationprinciple of periodic-random I/Q interleaving will be given later.

FIG. 31 is a view illustrating a periodic-random I/Q interleavingtechnology according to an embodiment of the present invention.

This figure illustrates, as described above, an embodiment in which theconstellation mapper and the cell interleaver are replaced by aQ1/Q2-delay block and the above-described periodic-random I/Qinterleaver. Here, the periodic-random I/Q interleaving technology maybe a concept including the Q1/Q2-delay block and the periodic-random I/Qinterleaver. In the following description, the periodic-random I/Qinterleaver may refer to only the periodic-random I/Q interleaver ofthis figure, or refer to the whole periodic-random I/Q interleavingtechnology including the Q1/Q2-delay block. The first block diagramillustrates an embodiment replaced in single-input and single-output(SISO) mode, and the second block diagram illustrates an embodimentreplaced in multiple-input and multiple-output (MIMO) mode.

The Q1/Q2-delay block may divide I components and Q components and thendelay only Q components. A delay value in this case may be determinedbased on use of 2D-SSD and use of 4D-SSD. The Q1-delay block may be usedin the case of 2D-SSD, and the Q2-delay block may be used in the case of4D-SSD.

The periodic-random I/Q interleaver may periodically write and randomlyread output of the Q1/Q2-delay block in and from memory. A period usedin this case may be determined based on use of 2D-SSD and use of 4D-SSD.

FIG. 32 is a view illustrating a Q1-delay process in the case of 2D-SSD,according to an embodiment of the present invention.

A description is now given of an operation process of a periodic-randomI/Q interleaving technology including the Q1-delay block and theperiodic-random I/Q interleaver in consideration of 2D-SSD. Here, thesize of memory and the number of input cells are assumed as N.

When 2D-SSD is considered, the Q1-delay block may delay the Q componentsby one cell, and then an output signal thereof may be input to theperiodic-random I/Q interleaver. In the figure illustrating the Q1-delayprocess according to an embodiment of the present invention, it is shownthat the I components are constantly maintained and only the Qcomponents are delayed by one cell. Since cyclic shifting is performed,an (N−1)^(th) Q component is paired with a 0^(th) I component.

FIG. 33 is a view illustrating operation of the periodic-random I/Qinterleaver in the case of 2D-SSD, according to an embodiment of thepresent invention.

When 2D-SSD is considered, the output signal of the Q1-delay block isinput to the memory and an input period in this case may be set to 2 toseparate neighboring I/Q components of 2D-SSD as far as possible. Assuch, 0^(th), 2^(nd), 4^(th), . . . , (N−2)^(th) cells may be written inthe memory, and then 1^(st), 3^(rd), 5^(th), . . . , (N−1)^(th) cellsmay be written in the memory. Consequently, this writing process relatesto an operation for improving periodicity of the interleaver.

After that, the random interleaver may read the signal stored in thememory and thus the interleaved signal may be ultimately output. Thereading process in this case may be performed based on an output indexof the random interleaver. The size of the random interleaver may beN/2, or the size of an index generated by the random interleaver may beN/2. Accordingly, 2 random interleavers may be necessary for the readingprocess. The output memory index of the random interleaver may begenerated using a quadratic polynomial (QP) algorithm or a pseudo-randombinary sequence (PRBS) generator. In addition, the same randominterleaver may be used for 2 periods in consideration of a writingperiod, and thus the principle of the writing process for spreadingneighboring I/Q components as far as possible may be constantlymaintained.

The above-described writing process may be expressed as given by thefollowing equation.

$\begin{matrix}{{{{\pi_{w}(k)} = {{\frac{N}{2}\mspace{11mu} {mod}\mspace{11mu} \left( {k,2} \right)} + \left\lfloor \frac{k}{2} \right\rfloor}},{0 \leq k \leq {N - 1}}}{N\text{:}\mspace{14mu} {total}\mspace{14mu} {cell}\mspace{14mu} {number}}{\left\lfloor \cdot \right\rfloor \text{:}\mspace{14mu} {floor}\mspace{14mu} {operation}}\text{}{{mod}\text{:}\mspace{14mu} {modulus}\mspace{14mu} {operation}}\text{}{{{\pi_{w}(k)}\text{:}\mspace{14mu} {writing}\mspace{14mu} {memory}} - {{index}\mspace{31mu} {for}\mspace{14mu} {the}\mspace{14mu} k^{th}\mspace{14mu} {cell}}}} & \left\lbrack {{Expression}\mspace{14mu} 12} \right\rbrack\end{matrix}$

In addition, the above-described reading process may be expressed asgiven by the following equation.

[Expression  13]${{\pi_{r}\left( k^{\prime} \right)} = {{\left( {\gamma + {q \times \frac{k\left( {k + 1} \right)}{2}}} \right)\mspace{11mu} {mod}\mspace{11mu} \frac{N}{2}\mspace{14mu} {for}\mspace{14mu} k^{\prime}} = 0}},\ldots \mspace{14mu},2^{n},{{{where}\mspace{14mu} \left\lceil {\log_{2}\left( {N/4} \right)} \right\rceil} < n \leq \left\lceil {\log_{2}\left( {N/2} \right)} \right\rceil}$${{{if}\mspace{14mu} 0} \leq {\pi_{r}\left( k^{\prime} \right)} \leq {\frac{N}{2} - 1}},{{\pi_{r}(k)} = {{{\frac{N}{2}g} + {{\pi_{r}\left( k^{\prime} \right)}{for}\mspace{14mu} k}} = 0}},\ldots \mspace{14mu},{\frac{N}{2} - 1},{g = 0},1$N:  total  cell  number ⌈⋅⌉:  ceil  operationmod:  modulus  operationγ:  an  offset  value  t  of  a  quadratic  polynomial  (Q P)g:  reading  period, i.e., g = 2  in  the  case  of  2D-SSDπ_(r)(k^(′)):  output  value  of  Q P  for  the  k^(‵)  orderπ_(r)(k):  reading  memory − index   for  the  k^(th)  cell

As shown in the above equations, the writing process improves spreadingproperty of the interleaver while the reading process improvesrandomness property of the interleaver.

The random interleaving process generates the memory index using, forexample, a QP algorithm. In this case, when the generated index isgreater than N/2−1, the index may not be used as a memory index valuebut may be discarded, and the QP algorithm may be executed once again.If the re-generated index is less than N/2−1, the index may be used as amemory index value to perform the reading process. Here, the QPalgorithm may be replaced by an arbitrary random interleaver such asPRBS.

FIG. 34 is a view illustrating operation of the periodic-random I/Qinterleaving technology in the case of 2D-SSD when N is 24, according toan embodiment of the present invention.

Even when N=24₉ periodic-random I/Q interleaving operates as describedabove. Q components are delayed by one cell through the Q1-delay block,a memory writing process is performed based on an input period of 2, anda memory reading process is performed, thereby performing randominterleaving.

The effect of the periodic-random I/Q interleaving technology may beshown using the example of the case in which N=24. When an output signalis compared to an input signal, it is shown that the periodic-random I/Qinterleaving technology includes both spreading and randomnessproperties.

FIG. 35 is a view illustrating a Q2-delay process in the case of 4D-SSD,according to an embodiment of the present invention.

A description is now given of an operation process of a periodic-randomI/Q interleaving technology including the Q2-delay block and theperiodic-random I/Q interleaver in consideration of 4D-SSD. Here, thesize of memory and the number of input cells are assumed as N.

When 4D-SSD is considered, the Q2-delay block may delay the Q componentsby two cells, and then an output signal thereof may be input to theperiodic-random I/Q interleaver. In the figure illustrating the Q2-delayprocess according to an embodiment of the present invention, it is shownthat the I components are constantly maintained and only the Qcomponents are delayed by two cells. Since cyclic shifting is performed,(N−2)^(th) and (N−1)^(th) Q components are paired with 0^(th) and 1^(st)I components.

FIG. 36 is a view illustrating operation of the periodic-random I/Qinterleaver in the case of 4D-SSD, according to an embodiment of thepresent invention.

When 4D-SSD is considered, the output signal of the Q2-delay block isinput to the memory and an input period in this case may be set to 4 toseparate I/Q components of two neighboring cells of 4D-SSD as far aspossible. As such, 0^(th), 4^(th), 8^(th), . . . , (N−4)^(th) cells maybe written in the memory, and then 1^(st), 5^(th), 9^(th), . . . ,(N−3)^(th) cells, 2^(nd), 6^(th), 10^(th), . . . , (N−2)^(th) cells, and3^(rd), 7^(th), 11^(th), . . . , (N−1)^(th) cells may be written in thememory. Consequently, this writing process relates to an operation forimproving periodicity of the interleaver.

After that, the random interleaver may read the signal stored in thememory and thus the interleaved signal may be ultimately output. Thereading process in this case may be performed based on an output indexof the random interleaver. The size of the random interleaver may beN/4, or the size of an index generated by the random interleaver may beN/4. Accordingly, 4 random interleavers may be necessary for the readingprocess. The output memory index of the random interleaver may begenerated using a quadratic polynomial (QP) algorithm or a pseudo-randombinary sequence (PRBS) generator. In addition, the same randominterleaver may be used for 4 periods in consideration of a writingperiod, and thus the principle of the writing process for spreading I/Qcomponents of two neighboring cells as far as possible may be constantlymaintained.

The above-described writing process may be expressed as given by thefollowing equation.

$\begin{matrix}{{{{\pi_{w}(k)} = {{\frac{N}{4}{{mod}\left( {k,2} \right)}} + \left\lfloor \frac{k}{4} \right\rfloor}},{0 \leq k \leq {N - 1}}}{N\text{:}\mspace{14mu} {total}\mspace{14mu} {cell}\mspace{14mu} {number}}{\left\lfloor \cdot \right\rfloor \text{:}\mspace{14mu} {floor}\mspace{14mu} {operation}}\text{}{{mod}\text{:}\mspace{14mu} {modulus}\mspace{14mu} {operation}}{{{\pi_{w}(k)}\text{:}\mspace{14mu} {writing}\mspace{14mu} {memory}} - {index}}{{for}\mspace{14mu} {the}\mspace{14mu} k^{th}\mspace{14mu} {cell}}} & \left\lbrack {{Expression}\mspace{11mu} 14} \right\rbrack\end{matrix}$

In addition, the above-described reading process may be expressed asgiven by the following equation.

[Expression  15]${{\pi_{r}\left( k^{\prime} \right)} = {{\left( {\gamma + {q \times \frac{k\left( {k + 1} \right)}{2}}} \right)\mspace{11mu} {mod}\mspace{11mu} \frac{N}{4}\mspace{14mu} {for}\mspace{14mu} k^{\prime}} = 0}},\ldots \mspace{14mu},2^{n},{{{where}\mspace{14mu} \left\lceil {\log_{2}\left( {N/8} \right)} \right\rceil} < n \leq {\left\lceil {\log_{2}\left( {N/4} \right)} \right\rceil {if}\mspace{14mu} 0} \leq {\pi_{r}\left( k^{\prime} \right)} \leq {\frac{N}{4} - 1}},{{\pi_{r}(k)} = {{{\frac{N}{4}g} + {{\pi_{r}\left( k^{\prime} \right)}{for}\mspace{14mu} k}} = 0}},\ldots \mspace{14mu},{\frac{N}{4} - 1},{g = 0},1,2,3$N:  total  cell  number ⌈⋅⌉:  ceil  operationmod:  modulus  operationγ:  an  offset  value  t  of  a  quadratic  polynomial  (Q P)g:  reading  period, i.e., g = 4  in  the  case  of  4D-SSDπ_(r)(k^(′)):  output  value  of  Q P  for  the  k^(‵)  orderπ_(r)(k):  reading  memory − index   for  the  k^(th)  cell

As shown in the above equations, the writing process improves spreadingproperty of the interleaver while the reading process improvesrandomness property of the interleaver.

The random interleaving process generates the memory index using, forexample, a QP algorithm. In this case, when the generated index isgreater than N/4−1, the index may not be used as a memory index valuebut may be discarded, and the QP algorithm may be executed once again.If the re-generated index is less than N/4−1, the index may be used as amemory index value to perform the reading process. Here, the QPalgorithm may be replaced by an arbitrary random interleaver such asPRBS.

FIG. 37 is a view illustrating operation of the periodic-random I/Qinterleaving technology in the case of 4D-SSD when N is 24, according toan embodiment of the present invention.

Even when N=24, periodic-random I/Q interleaving operates as describedabove. Q components are delayed by two cells through the Q2-delay block,a memory writing process is performed based on an input period of 4, anda memory reading process is performed, thereby performing randominterleaving.

The effect of the periodic-random I/Q interleaving technology may beshown using the example of the case in which N=24. When an output signalis compared to an input signal, it is shown that the periodic-random I/Qinterleaving technology includes both spreading and randomnessproperties.

FIG. 38 is a detailed block diagram of a demapping & decoding moduleaccording to another embodiment of the present invention.

As described above, a cell deinterleaver may deinterleave cells spreadwithin one FEC block, to original positions thereof. The celldeinterleaver performs an inverse operation of the operation of the cellinterleaver of the transmitter. In addition, an I-delay block of aconstellation demapper delays I components to restore Q componentsdelayed by the transmitter, to original positions thereof.

In the demapping & decoding module according to another embodiment ofthe present invention, the shaded blocks are modified from theabove-described demapping & decoding module.

The demapping & decoding module according to another embodiment of thepresent invention may include a periodic-random I/Q deinterleavingprocess. The periodic-random I/Q deinterleaving technology maycorrespond to operations of the cell deinterleaver and the I-delay blockin this figure. In addition, according to an embodiment, when celldeinterleaving is omitted, periodic-random I/Q deinterleaving may beperformed after time deinterleaving. Furthermore, according to anotherembodiment, when the cell deinterleaver is omitted, a time deinterleavermay perform periodic-random I/Q deinterleaving. In this case, the timedeinterleaver may perform only the periodic-random I/Q deinterleavingoperation, or perform the periodic-random I/Q deinterleaving operationand the above-described operation of the time deinterleaver in thenext-generation broadcast system.

FIG. 39 is a view illustrating a periodic-random I/Q deinterleavingtechnology according to an embodiment of the present invention.

This figure illustrates, as described above, an embodiment in which theconstellation demapper and the cell deinterleaver are replaced by theabove-described periodic-random I/Q deinterleaver and an I1/I2 delayblock. Here, the periodic-random I/Q deinterleaving technology may be aconcept including the periodic-random I/Q deinterleaver and theI1/I2-delay block. In the following description, the periodic-random I/Qdeinterleaver may refer to only the periodic-random I/Q deinterleaver ofthis figure, or refer to the whole periodic-random I/Q deinterleavingtechnology including the I1/I2-delay block. The first block diagramillustrates an embodiment replaced in single-input and single-output(SISO) mode, and the second block diagram illustrates an embodimentreplaced in multiple-input and multiple-output (MIMO) mode.

An overall operation process of the receiver may follow an inverse(restoration) process compared to the operation of the transmitter. Theperiodic-random I/Q deinterleaving technology corresponding to theinvented periodic-random I/Q interleaving technology may be as describedbelow.

The periodic-random I/Q deinterleaver randomly performs writingoperation in an opposite direction to the periodic-random I/Qinterleaver of the transmitter, and then periodically performs readingoperation. A mathematical expression or algorithm used in this case maybe the same as that used by the transmitter.

Output of the periodic-random I/Q deinterleaver is input to theI1/I2-delay block. The I1/I2-delay divides I components and Q componentsand then delays only the I components. A delay value in this case may bedetermined to 1 and 2 based on use of 2D-SSD and use of 4D-SSD. TheI1-delay block may be used in the case of 2D-SSD, and the I2-delay blockmay be used in the case of 4D-SSD. Consequently, the influence of theQ1/Q2-delay block operating in the transmitter may be offset by theI1/I2-delay.

FIG. 40 illustrates a part of a broadcast signal transmitter fornext-generation broadcast service according to another embodiment of thepresent invention.

Here, a bit interleaved coded modulation (BICM) encoder may correspondto the above-described coding & modulation module. In the currentembodiment, the BICM encoder may include an FEC encoder, a bitinterleaver, and/or a constellation mapper. According to an embodiment,the BICM encoder may further include a time interleaver. According to anembodiment, the time interleaver may be located after the constellationmapper.

Here, a framing & interleaving module may be a new concept including theabove-described frame builder and/or frequency interleaver. The framing& interleaving module according to the current embodiment may includethe time interleaver, the frame builder and/or the frequencyinterleaver. According to an embodiment, the framing & interleavingmodule may not include the time interleaver. According to an embodiment,the time interleaver may not be included in the BICM encoder or theframing & interleaving module but may be located between the BICMencoder and the framing & interleaving module.

The time interleaver according to an embodiment of the present inventionmay further include a cell interleaver, a block interleaver, and/or aconvolutional interleaver. Here, the cell interleaver may be theabove-described cell interleaver. When the cell interleaver is includedin the time interleaver, before time interleaving, the cell interleavermay interleave cells in FEC blocks in such a manner that the cells ofeach FEC block are output in a different order from cells of another FECblock. The block interleaver may perform block interleaving on TI blockseach including one or more FEC blocks. The block interleaver may performinterleaving by linearly writing cells or cell pairs in an FEC block ina column-wise direction, and reading the same in a diagonal-wisedirection. In the writing operation, a left part of memory may be filledwith virtual FEC blocks and a right part of the memory may be filledwith FEC blocks having actual data. In the reading operation, cells orcell pairs of these virtual FEC blocks may not be read but may beskipped. The convolutional interleaver may perform interleaving byspreading the block-interleaved TI blocks to a plurality of signalframes.

The present invention proposes another embodiment of the above-describedcell interleaver. The cell interleaver according to another embodimentof the present invention may interleave cells in one FEC block. Due tooperation of the cell interleaver, time diversity performance of thetime interleaver may be greatly improved. That is, the cell interleavermay improve time diversity of a burst channel environment in associationwith the time interleaver. In addition, the present invention proposes acell deinterleaver corresponding to the cell interleaver according toanother embodiment of the present invention. Cell interleaving proposedby the present invention may be performed to reduce or eliminate memoryused for cell deinterleaving.

The cell interleaver according to another embodiment of the presentinvention may randomly interleave cells in one FEC block. Such randomcell interleaving may be performed through linear writing and randomreading using an interleaving pattern.

Initially, the cell interleaver may linearly write cells of an FEC blockin the memory (linear writing). Here, the linearly writing operation mayrefer to an operation for sequentially writing the cells in the memoryby the cell interleaver.

After that, the cell interleaver may randomly read the cells linearlywritten in the memory (random reading). This random reading operationmay be performed using an interleaving pattern. Here, the interleavingpattern may be called an interleaving sequence, permutation sequence,interleaving seed, permutation function, memory address, randomsequence, or the like.

The cell interleaver may change the permutation sequence used for therandom reading operation, ever FEC block. Alternatively, according to anembodiment, the permutation sequence may be changed every pair of FECblocks. As the permutation sequence is changed every FEC block,randomness property of the cell interleaver may be improved.

Here, the permutation sequences for the FEC blocks may be generated byshifting one basic permutation sequence. In this case, the basicpermutation sequence may be a pseudo-random sequence.

When only one PLP is present (S-PLP), the above-described timeinterleaver may not include the cell interleaver. When only one PLP ispresent, cell interleaving may not be performed.

The cell deinterleaver according to another embodiment of the presentinvention may be a module of the receiver corresponding to theabove-described cell interleaver. The cell deinterleaver according toanother embodiment of the present invention may perform an inverseoperation of the operation of the above-described cell interleaver.

According to an embodiment, this cell deinterleaver may have a ping-pongstructure. In this case, the cell deinterleaver may use memory of an FECdecoder instead of using additional memory for the ping-pong structure.Accordingly, the receiver may not need additional memory for the celldeinterleaver even when the cell deinterleaver has a ping-pongstructure. This efficient use of memory is enabled because theabove-described cell interleaver has interleaved the cells throughlinear writing & random reading operation. A detailed description ofcell deinterleaving operation will be given below.

FIG. 41 is a view illustrating a basic switch structure according to anembodiment of the present invention.

As described above, according to an embodiment, a cell interleaver mayhave a ping-pong structure. A demux may send FEC blocks to specificmemory banks based on whether the FEC blocks are odd-numbered oreven-numbered. The even-numbered FEC blocks may be sent to memory bankA, and the odd-numbered FEC blocks may be sent to memory bank B. Thesent FEC blocks may be cell-interleaved and then sent to a mux. The muxmay align and output the received interleaved FEC blocks.

Here, mod may denote modulo operation, and j may have an integer valuebetween 0 and N_(FEC) _(_) _(block)−1. In this case, N_(FEC) _(_)_(block)−1 may denote the number of FEC blocks in an interleaving unit.

FIG. 42 is a view mathematically expressing linear writing & randomreading operation of the cell interleaver according to anotherembodiment of the present invention.

Equation t42010 of the figure shows an input vector of the cellinterleaver. X_(j) may be an input vector of a j^(th) FEC block.X_(j)(p) values included in X_(j) may individually indicate cells of thej^(th) FEC block. Here, p may have a value from 0 to N_(cells)−1. Inthis case, N_(cells) may denote the number of cells in the FEC block.

Equation t42020 of the figure shows an output vector, i.e., aninterleaved vector, of the cell interleaver. F_(j) may be an outputvector of the j^(th) FEC block. F_(j)(p) values included in F_(j) mayindividually indicate interleaved cells of the j^(th) FEC block. Here, pmay have a value from 0 to N_(cells). That is, the cells of the inputvector x, may be interleaved by the cell interleaver and thus the orderthereof may be changed into the form of F_(j).

Equation t42030 of the figure may be a mathematical expression of linearwriting & random reading operation of the cell interleaver. Due to thelinear writing & random reading operation, the order of the cells of theinput FEC block may be changed as indicated by the value of apermutation sequence. In the illustrated equation, the order of a k^(th)cell F_(j)(k) of the output vector may be changed to be the same as theorder of a C_(j)(k)^(th) cell X_(j)(C_(j)(k)) of the input vector. Thatis, the order may be randomly changed in such a manner that the k^(th)cell becomes the C_(j)(k)^(th) cell.

Here, C_(j)(k) is a random value generated by the above-described randomgenerator, and may correspond to the above-described permutationsequence. C_(j)(k) may be a permutation sequence for the j^(th) FECblock. This permutation sequence may be implemented using an arbitraryPRBS generator. The present invention is generally applicableirrespective of the PRBS generator.

Here, j may have an integer value between 0 and N_(FEC) _(_) _(block)−1.N_(FEC) _(_) _(block)−1 may denote the number of FEC blocks in aninterleaving unit. In addition, k may have a value from 0 toN_(cells)−1.

FIG. 43 is a view mathematically expressing a permutation sequencegenerating method of the cell interleaver according to anotherembodiment of the present invention cell interleaver.

As described above, a permutation sequence may be changed every FECblock. These permutation sequences may be generated by differentlyshifting one basic permutation sequence. This shifting process may beperformed using a shift value to be described below.

T(k) may be a basic permutation sequence generated by theabove-described random generator. This basic permutation sequence mayalso be called a main interleaving pattern. This basic permutationsequence may be used by a main cell interleaver. That is, the basicpermutation sequence is used to perform cell interleaving on the firstFEC block of a TI block.

S_(j) may be a shift value used for the j^(th) FEC block. S_(j) may beadded to T(k) and thus used to generate different permutation sequencesfor different FEC blocks. This shift value may be implemented using anarbitrary PRBS generator. That is, the present invention is generallyapplicable irrespective of the PRBS generator. According to anembodiment, the shift value may be subtracted from T(k) to generatedifferent permutation sequences for different FEC blocks.

After the shift value is reflected in the basic permutation sequence,modulo operation with N_(cells) may be performed. N_(cells) may denotethe number of cells in a corresponding FEC block. Due to modulooperation with N_(cells), constant shifting may be performed on thebasic permutation sequence. As such, different permutation sequences maybe generated for different FEC blocks.

FIG. 44 illustrates a part of a broadcast signal receiver fornext-generation broadcast service including a cell deinterleaveraccording to another embodiment of the present invention.

The cell deinterleaver according to another embodiment of the presentinvention may be a block corresponding to the above-described cellinterleaver. The cell deinterleaver may perform an inverse operation ofthe operation of the cell interleaver of the transmitter. The celldeinterleaver may restore cells interleaved in one FEC block to originalpositions thereof. An algorithm of cell deinterleaving operation may beperformed inversely from the algorithm of cell interleaving operation.

That is, the cell deinterleaver may randomly write cells of an FEC blockin memory and then linearly read the written cells (random writing &linear reading). The random writing operation may be performed using apermutation sequence. The linear reading operation may refer to anoperation for sequentially reading the cells written in the memory.

In addition, the cell deinterleaver according to another embodiment ofthe present invention may not perform cell deinterleaving on output of atime deinterleaver. Cell deinterleaving may be performed when the outputof the time deinterleaver is stored in FEC decoding memory after anadditional decoding process, e.g., constellation demapping, is performedthereon. When data is stored in the FEC decoding memory, the data may bestored in consideration of cell deinterleaving using address valuesgenerated by an address generator. That is, memory of an FEC decoder maybe used for cell deinterleaving. Consequently, the receiver may not needadditional memory for cell deinterleaving, and thus efficient dataprocessing operation of the receiver may be enabled.

According to an embodiment, the cell deinterleaver according to anotherembodiment of the present invention may be located in the timedeinterleaver or located after the time deinterleaver.

FIG. 45 is a view illustrating a broadcast signal transmitting methodaccording to an embodiment of the present invention.

The broadcast signal transmitting method according to an embodiment ofthe present invention may include formatting an input stream into aplurality of PLPs, encoding data of the PLPs, performing timeinterleaving, mapping the data to one or more signal frames, and/orperforming waveform modulating & transmission.

In the current embodiment, initially, an input formatting block mayformat an input stream into a plurality of PLPs (t45010). Here, theinput formatting block may be the above-described input formattingmodule. The input stream may be a TS, GS, or IP stream as describedabove. The PLPs may be the above-described DPs.

After that, data of the PLPs may be encoded by an encoder (t45020).Here, the encoding process may be a concept including a series of theabove-described operations such as FEC encoding and bit interleaving.The operations included in the encoding process may vary according to anembodiment. According to an embodiment, the encoder may include an FECencoder, a bit interleaver, and a constellation mapper. According to anembodiment, this encoder may be called a BICM encoder.

The data of the PLPs may be time-interleaved by a time interleaver(t45030). This process may be performed by the above-described timeinterleaver. According to an embodiment, the time interleaver may beincluded in the BICM encoder, or located outside the BICM encoder totime-interleave output of the BICM encoder.

As described above, the time interleaver may include a cell interleaver.The cell interleaver may perform cell interleaving on the data of thePLPs by changing the order of cells in one FEC block. The cellinterleaving process may be performed before the above-described blockinterleaving process.

The data of the PLPs may be mapped to frames by a framer (t45040). Here,the framer may correspond to the above-described frame builder, or thecell mapper included therein. The framer may map the PLP data, on whichvarious processes are performed, to one or more signal frames.

Data of the above-described signal frames may be modulated throughwaveform modulation (t45050). The waveform modulation process isperformed by a waveform module. According to an embodiment, the waveformmodule may also be called an OFDM module. Due to operation of thewaveform module, frequency-interleaved data may be modulated, and themodulated data may be transmitted in a broadcast signal (t45050).According to an embodiment, the waveform module may include at least oneantenna.

In a broadcast signal transmitting method according to anotherembodiment of the present invention, the cell interleaver may performcell interleaving on cells in one FEC block by performing linear writing& random reading operation on memory. The cell interleaver maysequentially write the cells of the FEC block in the memory, andrandomly read the cells from the memory using a permutation sequence.

In the broadcast signal transmitting method according to anotherembodiment of the present invention, the permutation sequence of eachFEC block may differ from that of another FEC block. That is, thepermutation sequence may be changed based on an FEC block index.

In the broadcast signal transmitting method according to anotherembodiment of the present invention, the permutation sequences fordifferent FEC blocks may be determined by differently shifting a basicpermutation sequence. Here, the basic permutation sequence may includeone or more sequences. According to an embodiment, the permutationsequences may be determined by changing the basic permutation sequenceusing a scheme other than shifting.

In the broadcast signal transmitting method according to anotherembodiment of the present invention, the permutation sequence may begenerated by adding a shifting value to the basic permutation sequenceand performing modulo operation with the number of cells (N_(cells)) inthe FEC block. Here, the shifting value may differ every FEC block. Thatis, the shifting value may have the FEC block index as a variable.

In the broadcast signal transmitting method according to anotherembodiment of the present invention, the basic permutation sequence maybe a pseudo-random sequence.

In the broadcast signal transmitting method according to anotherembodiment of the present invention, the time interleaver may furtherinclude a block interleaver and a convolution delay line block. Here,the convolution delay line block may also be called a convolutionalinterleaver. After cell interleaving, the block interleaver may performblock interleaving. The block interleaving process may be performed byinterleaving time interleaving (TI) blocks each including one or moreFEC blocks. After block interleaving, the convolution delay line blockmay perform convolutional interleaving. The convolutional interleavingprocess may be performed by interleaving the TI blocks.

In the broadcast signal transmitting method according to anotherembodiment of the present invention, the above-described encoder mayinclude an FEC encoder, a bit interleaver, and/or a constellationmapper. That is, the above-described step for encoding the data of thePLPs may include performing FEC encoding on the PLP data, performing bitinterleaving, and/or performing constellation mapping. In the step forperforming constellation mapping, the constellation mapper mayconstellation-map the bit-interleaved data to FEC blocks by mapping thePLP data to constellations.

A description is now given of a broadcast content receiving methodaccording to an embodiment of the present invention. The broadcastcontent receiving method according to an embodiment of the presentinvention is not illustrated in any figure.

The broadcast content receiving method according to an embodiment of thepresent invention may include receiving a broadcast signal andperforming waveform demodulating, performing frame parsing by demappinga plurality of PLPs, performing time deinterleaving on data of the PLPs,decoding the data of the PLPs, and/or outputting an output stream byoutput-processing the data of the PLPs.

In the current embodiment, a waveform module inside/outside the receivermay receive a broadcast signal including one or more signal frames.Here, the waveform module may perform operation corresponding to theabove-described waveform module of the transmitter. The waveform modulemay demodulate data of the signal frames. According to an embodiment,the waveform module may include at least one antenna and/or tuner.According to an embodiment, the waveform module may also be called anOFDM module.

A frame parser may parse the data of the signal frames by demapping aplurality of PLPs. Data of the PLPs may be demapped from the signalframes. The frame parser may be the above-described cell demapper orframe parser.

A time deinterleaver may perform time deinterleaving on the PLP data.The time deinterleaver may be located inside or outside a BICM decoder.The current embodiment assumes that the time deinterleaver is notincluded in the BICM decoder.

The time deinterleaver may include a cell deinterleaver as describedabove. The cell deinterleaver may change the order of cells in one FECblock of the PLPs. As such, the cells in the FEC block may be restoredto original positions thereof. According to an embodiment, the celldeinterleaver may be located outside the time deinterleaver.

The PLP data may be decoded by a decoder. This decoder may be called aBICM decoder. The decoder may include a constellation demapper, a bitdeinterleaver, and/or an FEC decoder.

An output processing block may perform output processing on the decodeddata of the PLPs. As such, the output processing block may output anoutput stream. Here, the output processing block may correspond to theabove-described output processing module.

According to an embodiment, the above-described steps may be omitted ormay be replaced by other steps for performing the same or similaroperations.

FIG. 46 is a view illustrating a broadcast signal transmitter accordingto an embodiment of the present invention.

The broadcast signal transmitter according to an embodiment of thepresent invention may include the above-described input formattingblock, the encoder, the time interleaver, the framer, and/or thewaveform block. The time interleaver may further include the cellinterleaver, the block interleaver, and/or the convolution delay lineblock. The encoder may further include the FEC encoder, the bitinterleaver, and/or the constellation mapper. Descriptions of the blocksand modules are as given above.

The broadcast signal transmitter according to an embodiment of thepresent invention and the modules/blocks included therein may implementembodiments of the above-described broadcast signal transmitting methodaccording to the present invention.

A description is now given of a broadcast content receiver according toan embodiment of the present invention. This broadcast content receiveris not illustrated in any figure.

The broadcast content receiver according to an embodiment of the presentinvention may include the above-described waveform block, the frameparser, the time deinterleaver, the decoder, and/or the outputprocessing block. The time deinterleaver may include the convolutiondelay line block, the block deinterleaver, and/or the celldeinterleaver. The decoder may further include the constellationdemapper, the bit deinterleaver, and/or the FEC decoder. Descriptions ofthe blocks and modules are as given above.

The broadcast signal receiver according to an embodiment of the presentinvention and the modules/blocks included therein may implementembodiments of the above-described broadcast signal receiving methodaccording to the present invention.

The above-described input formatting block, the encoder, the timeinterleaver, the framer, the waveform block, the cell interleaver, theblock interleaver, the convolution delay line block, the FEC encoder,the bit interleaver, the constellation mapper, the waveform block, theframe parser, the time deinterleaver, the decoder, the output processingblock, the convolution delay line block, the block deinterleaver, thecell deinterleaver, the constellation demapper, the bit deinterleaver,and/or the FEC decoder may be processors for executing sequentialprocesses stored in memory, and may be hardware elements locatedinside/outside the transmitter/receiver according to an embodiment.

According to an embodiment, the above-described modules may be omittedor may be replaced by other modules for performing the same or similaroperations.

Although the description of the present invention is explained withreference to each of the accompanying drawings for clarity, it ispossible to design new embodiment(s) by merging the embodiments shown inthe accompanying drawings with each other. And, if a recording mediumreadable by a computer, in which programs for executing the embodimentsmentioned in the foregoing description are recorded, is designed innecessity of those skilled in the art, it may belong to the scope of theappended claims and their equivalents.

An apparatus and method according to the present invention may benon-limited by the configurations and methods of the embodimentsmentioned in the foregoing description. And, the embodiments mentionedin the foregoing description can be configured in a manner of beingselectively combined with one another entirely or in part to enablevarious modifications.

In addition, a method according to the present invention can beimplemented with processor-readable codes in a processor-readablerecording medium provided to a network device. The processor-readablemedium may include all kinds of recording devices capable of storingdata readable by a processor. The processor-readable medium may includeone of ROM, RAM, CD-ROM, magnetic tapes, floppy discs, optical datastorage devices, and the like for example and also include such acarrier-wave type implementation as a transmission via Internet.Furthermore, as the processor-readable recording medium is distributedto a computer system connected via network, processor-readable codes canbe saved and executed according to a distributive system.

It will be appreciated by those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

Both apparatus and method inventions are mentioned in this specificationand descriptions of both of the apparatus and method inventions may becomplementarily applicable to each other.

Various embodiments have been described in the best mode for carryingout the invention.

The present invention is available in a series of broadcast signalprovision fields.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method of transmitting broadcast signals, themethod including: encoding service data in plural PLPs (Physical LayerPipes); cell interleaving the encoded service data, wherein the cellinterleaving further includes: linear writing cells in each FEC block ofthe encoded service data; and random reading the written cells based ona shift value; interleaving each TI (Time Interleaving) block of thecell interleaved service data; mapping the interleaved service data intoat least one signal frame; modulating data in the at least one signalframe; and transmitting the broadcast signals having the modulated data.2. The method of claim 1, wherein the shift value is added to a basicinterleaving sequence to generate different interleaving sequence forthe random reading over the each FEC block.
 3. The method of claim 2,wherein the shift value is different per a FEC block.
 4. The method ofclaim 3, wherein a modulo operation is applied to the basic interleavingsequence to which the shift value is added.
 5. The method of claim 1,wherein the interleaving each TI block of the cell interleaved servicedata further includes: column-wise writing at least one virtual FECblock and at least one FEC block, wherein the at least one virtual FECblock is included in at least one TI block having the at least one FECblock; diagonal-wise reading out cells from the written at least onevirtual FEC block and the written at least one FEC block, wherein cellsbelongs to the at least one virtual FEC block is skipped.
 6. Anapparatus of transmitting broadcast signals, the apparatus including: anencoder to encode service data in plural PLPs (Physical Layer Pipes); acell interleaver to cell interleave the encoded service data, whereinthe cell interleaver further linearly writes cells in each FEC block ofthe encoded service data and randomly reads out the written cells basedon a shift value; an interleaver to interleave each TI (TimeInterleaving) block of the cell interleaved service data; a framebuilder to map the interleaved service data into at least one signalframe; a modulator to modulate data in the at least one signal frame;and a transmitter to transmit the broadcast signals having the modulateddata.
 7. The apparatus of claim 6, wherein the shift value is added to abasic interleaving sequence to generate different interleaving sequencefor the random reading over the each FEC block.
 8. The apparatus ofclaim 7, wherein the shift value is different per a FEC block.
 9. Theapparatus of claim 8, wherein a modulo operation is applied to the basicinterleaving sequence to which the shift value is added.
 10. Theapparatus of claim 6, wherein the interleaver further performs:column-wise writing at least one virtual FEC block and at least one FECblock, wherein the at least one virtual FEC block is included in atleast one TI block having the at least one FEC block; diagonal-wisereading out cells from the written at least one virtual FEC block andthe written at least one FEC block, wherein cells belongs to the atleast one virtual FEC block is skipped.